…wenLM#3831 PR-1 of 3) (QwenLM#3842)

* feat(core): add signal.reason convention for ShellExecutionService.execute()

Foundation for QwenLM#3831 Phase D (b) — Ctrl+B promote of a running foreground
shell to background. Defines a discriminated `ShellAbortReason` union that
the AbortSignal carries; default behavior (no reason / `{ kind: 'cancel' }`)
keeps the existing tree-kill on abort. `{ kind: 'background' }` is a takeover
signal — execute() skips the kill, drops the child from its active set (so
cleanup() won't kill it later), flushes a snapshot of captured output, and
resolves the result Promise immediately with `promoted: true` so the
awaiting caller unblocks.

Pure plumbing: no caller sets the reason yet, so this is a zero-behavior
change for existing call sites. The `promoted?: boolean` field is optional
on ShellExecutionResult so existing consumers compile against the new shape
without source changes.

Tests pin both branches in both childProcessFallback and executeWithPty:
default abort still SIGTERM-tree-kills; `{ kind: 'cancel' }` is identical to
default (pin against accidental routing through the background branch);
`{ kind: 'background' }` skips the kill, snapshot output is preserved,
mockProcessKill / mockPtyProcess.kill are NOT called.

Part of QwenLM#3831 (Phase D part b — Ctrl+B promote running shell to background).
PR-1 of 3.

* fix(core): detach service listeners on background-promote (resolve review)

Addresses 4 Critical + 2 Suggestion findings on PR-1 of QwenLM#3831:

- **childProcess listener detach** (review line 555 + 573): Anonymous arrow
  listeners on stdout/stderr/error/exit could not be off()'d. After
  background-promote, post-promote bytes would re-enter handleOutput, which
  then calls decoder.decode() on a now-finalized text decoder (cleanup()
  already called .decode() without stream:true) → TypeError crash. Even
  without the crash, old onOutputEvent would fire for new data → ownership
  contract violation + duplication. Fix: extract named handler refs
  (stdoutHandler / stderrHandler / errorHandler / exitHandler) and call
  off() on all four in the background-promote branch via a
  detachServiceListeners() helper.

- **PTY listener detach** (review line 967 + 990): node-pty's onData / onExit
  return IDisposable handles; the abort handler now captures
  dataDisposable / exitDisposable and calls .dispose() in the
  background-promote branch. ptyProcess.on('error') is EventEmitter-style
  (not IDisposable) — extract a named ptyErrorHandler ref and off() it.
  Without these, post-promote PTY error throws → Node.js crash; post-promote
  data continues writing to headlessTerminal and calling old onOutputEvent
  → ownership violation.

- **PTY in-flight chain item ownership** (related to review line 990):
  processingChain may have already-enqueued callbacks past the early
  listenersDetached check. Refactored from "early-return short-circuit" to
  "guard each onOutputEvent emit individually" so in-flight writes still
  LAND in headlessTerminal (snapshot reflects them) but no events leak to
  the foreground onOutputEvent. Also clear renderTimeout in the abort
  handler so a pending throttled render doesn't fire post-promote.

- **PTY snapshot freshness** (review line 972, suggestion): The original
  abort handler called serializeTerminalToText immediately. Now we
  await Promise.race([processingChain drain, SIGKILL_TIMEOUT_MS]) first
  (mirrors the onExit finalize pattern at ~line 970) so in-flight
  headlessTerminal.write callbacks land before serialization. Skipped
  render(true) intentionally because it would emit final onOutputEvent
  data (renderFn calls onOutputEvent), violating the "no emit post-promote"
  invariant — added a comment explaining why direct serialize is correct.

- **Handoff-boundary tests** (review line 1257, suggestion): Added 4 new
  tests pinning the ownership contract — 2 for child_process (post-promote
  stdout/stderr does NOT route to onOutputEvent; child exit does NOT
  re-resolve result), 2 for PTY (data/exit disposables ARE called; result
  shape stays promoted: true even if post-promote events fire).

Also: test setup now stubs mockPtyProcess.onData / .onExit to return
{ dispose: vi.fn() } so the background-promote path's dispose() calls
don't crash on undefined (the stub's mock.results[0].value is then
inspected by the new handoff tests).

58 / 58 tests pass (50 baseline + 4 first-pass + 4 handoff). Total +235 / -35
on top of the prior commit.

* fix(core): defensive hardening for ShellExecutionService background-promote (resolve 2nd review pass)

Addresses 6 follow-up [Suggestion] threads on PR-1 of QwenLM#3831 — all
substantive code-quality issues raised by the second-pass review of
the dispose-based detach commit (8e8e18c):

- **Exhaustive switch on `ShellAbortReason.kind`** (both abort handlers).
  Earlier `if (reason?.kind === 'background')` form silently fell
  through to kill for any unrecognized variant — a future
  `{ kind: 'suspend' }` would have killed the process with zero
  compile-time signal. Switched to `switch (kind)` with a `never`-typed
  default that runs `debugLogger.warn` and falls back to the safest
  behavior (cancel/kill). Each branch is now extracted into a named
  helper (`performBackgroundPromote` / `performCancelKill`) so the
  switch body stays a single screenful.

- **Each `dispose()` wrapped in its own try/catch** (PTY). node-pty's
  `IDisposable` contract doesn't guarantee no-throw. Without per-dispose
  try/catch a single throwing dispose() would skip subsequent cleanup
  (the other dispose, off('error'), activePtys.delete, drain, resolve)
  and the caller would hang forever on `await result`. Each call now
  logs via debugLogger.warn on failure but continues.

- **`.catch(() => undefined)` on the processingChain side of the drain
  race** (PTY). `Promise.race([processingChain.then(drain).then(drain),
  timeout])` would propagate a chain rejection out of the race; since
  `addEventListener` doesn't await our handler, the rejection became
  unhandled and `resolve()` was never called → caller hung. Now the
  rejection is swallowed; the timeout side still terminates the race
  on time.

- **Drain-timeout truncation now emits a diagnostic warning** (PTY).
  Previously the 200ms drain timeout could fire, the snapshot would be
  taken with the buffer in mid-write state, and the result.output
  would be silently truncated. Race result is now observed via a
  symbol sentinel; when the timeout side wins, debugLogger.warn fires
  pointing the user at rawOutput as the un-truncated fallback.

- **Snapshot serialize failure logs instead of swallowing silently**
  (PTY). Empty `catch {}` made result.output indistinguishable from
  "command produced no output" if serializeTerminalToText threw. Now
  `debugLogger.warn` with the error message leaves a trail for support
  bundles.

- **Dedicated `PROMOTE_DRAIN_TIMEOUT_MS` constant** separated from
  `SIGKILL_TIMEOUT_MS`. Both are 200ms today, but they have unrelated
  reasons-to-change (kill escalation timing vs. promote drain
  ceiling) — sharing the constant means tuning one would silently
  change the other.

Also adds a module-level `debugLogger = createDebugLogger('SHELL_EXECUTION')`
since the service had no logging surface before this commit.

58 / 58 tests pass; tsc clean; ESLint clean. No new tests added: the new
behaviors (timeout sentinel firing, dispose throw, exhaustive switch
default) are defensive log-only paths; existing handoff tests already
cover the happy path. Adding mock-throw tests is reasonable
follow-up but not blocking.

* fix(core): real bug — ptyProcess.off → removeListener; defensive abort-reason read

Resolves the third review pass on PR-1 of QwenLM#3831 — 1 real bug + 2
defensive hardenings:

- **Real bug: `ptyProcess.off('error', ...)` throws TypeError at
  runtime** (line ~1074). `@lydell/node-pty`'s `IPty` interface
  exposes the legacy Node EventEmitter `removeListener`, not the
  modern `off` alias. Previous form threw, the surrounding try/catch
  swallowed it (post-prior-pass dispose hardening), but the old
  `ptyErrorHandler` stayed registered — so a post-promote PTY error
  would still hit our foreground handler and `throw err`, breaking
  the handoff contract that PR-1's whole listener-detach work is
  supposed to enforce. Switched to `removeListener`. The catch +
  warn stays as defense-in-depth; the message wording is updated.

- **Prototype-pollution-safe `kind` read** (extracted to module-level
  helper `getShellAbortReasonKind`). The previous `reason?.kind`
  walked the prototype chain — a polluted
  `Object.prototype.kind = 'background'` would silently route
  `abortController.abort({})` (any plain object reason) into the
  promote branch and skip the kill. Lifecycle/safety branch deserves
  the extra check. Helper now: rejects non-object reasons; reads
  `kind` only as an OWN property (`hasOwnProperty`); whitelists
  against `'background' | 'cancel'`; defaults to `'cancel'` (the
  safe historical behavior) for everything else. Both abort handlers
  (childProcess + PTY) now share this helper.

- **`streamStdout: true` + background-promote = silent empty
  snapshot** (childProcess `performBackgroundPromote`). The promote
  snapshot reads from the `stdout` / `stderr` string accumulators;
  but in `streamStdout` mode `handleOutput` forwards bytes through
  `onOutputEvent` and skips the accumulators entirely. Today PR-1's
  only call site (foreground shell.ts) uses `streamStdout: false`,
  so the combination is unreachable — but if a future caller pairs
  the two, `result.output` would be empty with no diagnostic. Added a
  `debugLogger.warn` when the combination occurs, pointing the caller
  at `rawOutput` as the fallback. Cheaper than building a parallel
  accumulator just for this latent case.

58 / 58 tests pass; tsc clean; ESLint clean.

* fix(core): liveness check + throw-safe abort-reason read + encoding-aware PTY snapshot (resolve 4th review pass)

Resolves 6 threads on PR-1 of QwenLM#3831 — 1 Critical + 1 real bug + 2
quality + 2 test-coverage:

- **[Critical] `getShellAbortReasonKind` throw-safe property read.**
  Previous form read `reason.kind` after only checking that `kind` is
  an own property. An own accessor that throws (or a Proxy with a
  trapping getter) would throw before the helper reached either the
  cancel kill path or the background promote path. Abort handlers are
  dispatched async and not awaited by AbortSignal, so a leaked throw
  here would have left the shell process alive instead of being killed
  on cancel — quietly. Wrapped the property read in try/catch with a
  fall-back to the safe 'cancel' kill behavior.

- **Real bug: child_process post-exit race in background-promote**
  (`performBackgroundPromote`). The child may have already exited but
  the 'exit' event hasn't reached our handler yet (Node delivers
  events on the next microtask). Promoting in that window would
  detach our exit listener and report `promoted: true` for a process
  that's already dead — the caller would hold an inert pid expecting
  to take over. Now we read `child.exitCode` / `child.signalCode`
  before detaching: if either is non-null, fall through and let the
  pending exit handler resolve normally with the real exit info.
  Mirrored mock setup so `exitCode` / `signalCode` default to `null`
  (matching real ChildProcess) instead of `undefined`.

- **PTY snapshot: re-decode + replay (mirror exit-path encoding).**
  The promoted snapshot was serializing `headlessTerminal` directly,
  which was fed by a streaming decoder initialized from the
  first-chunk encoding heuristic. When early output is ASCII-only but
  later output is in a different encoding (GBK / Shift-JIS / etc.),
  this produces mojibake — and the normal exit path doesn't, because
  it re-decodes `finalBuffer` with `getCachedEncodingForBuffer` and
  replays through a fresh terminal. Now mirrors that logic so
  `result.output` shape matches across the two paths. Direct-serialize
  remains as a last-ditch fallback if replay throws.

- **Switch `default` no longer emits a runtime warn.** Reviewer noted
  the helper's whitelist made the `default: { _exhaustive: never }`
  branch unreachable at runtime — the `debugLogger.warn` in it could
  never fire. Kept the `_: never = kind` type assertion (so a future
  ShellAbortReason variant forces a TS error here, directing the
  developer to extend BOTH the helper's whitelist AND add a `case`),
  removed the unreachable warn. Added a comment that the assertion is
  the static-only safety net the union expansion would trigger.

- **Direct unit tests for `getShellAbortReasonKind`** (8 cases). The
  helper's prototype-pollution defense is the main reason it exists;
  if `hasOwnProperty` is accidentally removed the regression would
  silently send `abortController.abort({})` (any plain reason) into
  the promote path. Exported the helper and added direct tests for:
  null / undefined, non-object, empty object (no own kind), prototype-
  only kind (pollution), unknown kind value, throwing accessor, Proxy
  trap, and the two happy paths.

- **`removeListener` regression guard.** The fix to call
  `ptyProcess.removeListener('error', ...)` instead of `.off(...)`
  matters because `@lydell/node-pty`'s IPty interface only exposes
  `removeListener` — `.off()` throws TypeError on a real PTY but the
  EventEmitter mock tolerates both. Added a test that spies on both
  methods and asserts the production code uses `removeListener` for
  the 'error' event, so a future swap back to `.off()` regresses
  loudly under the mock instead of silently.

68 / 68 tests pass (58 baseline + 9 helper boundary + 1 removeListener
guard + 1 post-exit race); tsc clean; ESLint clean.

* fix(core): PTY background-promote post-exit race guard (resolve 5th review pass)

Mirrors the child_process post-exit race fix from 4cc558b into the
PTY path — addresses 1 [Critical] thread on PR-1 of QwenLM#3831:

The PTY may have already exited but our `exitDisposable` (onExit
callback) hasn't run yet — node-pty delivers the exit event
asynchronously after the PTY's native SIGCHLD, so there's a window
between "PTY actually dead" and "service onExit fires". Promoting in
that window detaches our exit listener and reports `promoted: true`
for a dead PTY, losing the real exit status; the caller would hold an
inert pid expecting to take over.

The IPty interface doesn't expose an `exitCode` field we can read
directly (unlike `child.exitCode` / `child.signalCode` for
child_process), so use `process.kill(pid, 0)` as a best-effort
liveness check via the existing `ShellExecutionService.isPtyActive`
helper. If kill(pid, 0) throws ESRCH, the pid is gone — log at debug
level and fall through, letting the pending onExit callback resolve
normally with the real exit info.

Also adds a unit test mirroring the child_process race test: mocks
`process.kill(pid, 0)` to throw ESRCH on the liveness probe, asserts
the result has no `promoted: true` and reports the real exitCode.

69 / 69 tests pass; tsc clean; ESLint clean.

* docs(core): correct getShellAbortReasonKind boundary-test count in JSDoc

Doc said 'all six edge cases' but the test suite has 8 cases (added
Proxy-trap and undefined later). Off-by-2 cosmetic only — no behavior
change. Caught during a multi-round self-audit of PR-1 of QwenLM#3831.

Audit summary: 7 rounds (correctness / reverse / consistency / coverage
/ build / exception paths / style) found one false-positive (a sync-
abort registration-order race I initially thought existed). Verified
that Node's WHATWG AbortSignal does NOT auto-fire 'abort' listeners
on already-aborted signals, so the race window cannot open. No code
change needed for that scenario; this commit is just the JSDoc fix.

69 / 69 tests still pass; tsc + ESLint clean.

* docs(core): document the helper / union / switch sync invariant explicitly

Multi-round self-audit found that `getShellAbortReasonKind`'s value
whitelist has no compile-time tie to the `ShellAbortReason` union: when
the union grows, TypeScript's `_exhaustive: never` in each switch
forces #3 (the case arm) to be added, but the helper's whitelist
(#2) silently keeps degrading the new variant to 'cancel', and the
new case arm is never reached at runtime.

Reviewer #4 raised this on the second pass; the original commit chose
to accept it (option B in that thread) but didn't leave a strong
in-code signal for future contributors. Added an INVARIANT block
inside the helper enumerating the three sites that must be kept in
sync, so the next person extending `ShellAbortReason` sees the
coupling at the place where they're most likely to forget it.

No behavior change — comment-only. 69 / 69 tests still pass; tsc +
ESLint clean.

Audit summary (this round + prior round): 18 angles total over two
sweeps and one reverse-attack pass. Found:
  - 0 real bugs
  - 1 false-positive race (sync-abort registration order — Node WHATWG
    AbortSignal does NOT auto-fire on already-aborted signals;
    investigated, reverted)
  - 1 cosmetic doc fix (boundary-test count off-by-2)
  - 1 cosmetic INVARIANT block (this commit)

Areas reviewed without finding new issues: caller-side
ShellExecutionResult shape compatibility (optional `promoted?` field,
existing callers spread-untouched); `exited` flag lifecycle
(monotonic, cleanup() idempotent); processingChain in-flight
ownership (listenersDetached guards every onOutputEvent emit
including the renderFn-rendered case via the same flag); race
between exit event and abort handler (both microtasks, FIFO ordering
gives correct outcome either way); Node version dependence
(`AbortSignal.reason` is Node 17.2+, engines: >=20 covers it);
test isolation (mockImplementationOnce + module-level mockProcessKill
clears each beforeEach); `process.kill(pid, 0)` Windows liveness
reliability (best-effort, acceptable for PR-1 plumbing); PID reuse
race on the PTY liveness check (theoretically possible, microsecond
window, unavoidable at the OS level — rejected in spec discussion);
PR-2/PR-3 contract surface (caller MUST attach listeners before
abort — documented; any future caller violating this is its own bug).

* test(core): align mockChildProcess.exitCode/signalCode in second beforeEach

The 'execution method selection' describe block has its own
beforeEach (separate from 'child_process fallback') that builds
mockChildProcess but does not set `exitCode` / `signalCode = null`.
Real Node `ChildProcess.exitCode` / `signalCode` are `null` while the
process is alive — and production now reads these in the
background-promote race guard. The current tests in this block don't
exercise the promote path, so they pass regardless, but any future
promote-related test landing here would silently trip the guard
(`undefined !== null` is true) and fall through to the normal-exit
branch instead of promoting.

Mirror the `child_process fallback` block's mock setup so the two
beforeEach hooks produce equivalent ChildProcess shapes, eliminating
a quiet foot-gun for future contributors.

Comment-only / test-fixture change. 69 / 69 tests still pass; tsc clean.
Found during a deeper third-round self-audit of PR-1 of QwenLM#3831.

…wenLM#3115)

* feat: add commit attribution with per-file AI contribution tracking via git notes

Track character-level AI vs human contributions per file and store
detailed attribution metadata as git notes (refs/notes/ai-attribution)
after each successful git commit. This enables open-source AI disclosure
and enterprise compliance audits without polluting commit messages.

* feat: enhance commit attribution with real AI/human ratios and generated file exclusion

- Replace line-based diff with a prefix/suffix character-level algorithm
  for precise contribution calculation (e.g. "Esc"→"esc" = 1 char, not whole line)
- Compute real AI vs human contribution percentages at commit time by analyzing
  git diff --stat output: humanChars = max(0, diffSize - trackedAiChars)
- Add generated file exclusion (lock files, dist/, .min.js, .d.ts, etc.)
  ported from an existing generatedFiles.ts
- Add file deletion tracking via recordDeletion()
- Update git notes payload format: {aiChars, humanChars, percent} per file
  with real percentages instead of hardcoded 100%

* feat: add surface tracking, prompt counting, session persistence, and PR attribution

Align with the full attribution feature set:
- Surface tracking: read QWEN_CODE_ENTRYPOINT env var (cli/ide/api/sdk),
  include surfaceBreakdown in git notes payload
- Prompt counting: incrementPromptCount() hooked into client.ts message
  loop, tracks promptCount/permissionPromptCount/escapeCount
- Session persistence: toSnapshot()/restoreFromSnapshot() for serializing
  attribution state; ChatRecordingService.recordAttributionSnapshot()
  writes to session JSONL; client.ts restores on session resume
- PR attribution: addAttributionToPR() in shell.ts detects `gh pr create`
  and appends "🤖 Generated with Qwen Code (N-shotted by Qwen-Coder)"
- Session baseline: saves content hash on first AI edit of each file
  for precise human/AI contribution detection
- generatePRAttribution() method for programmatic access

* fix: audit fixes — initial commit handling, cron prompt exclusion, failed commit counter preservation

- Handle initial commit (no HEAD~1) by detecting parent with rev-parse
  and falling back to --root for first commit in repo
- Exclude Cron-triggered messages from promptCount (not user-initiated)
- Add commitSucceeded parameter to clearAttributions() so failed/disabled
  commits don't reset the prompts-since-last-commit counter
- Add test for clearAttributions(false) behavior

* fix: cross-platform and correctness fixes from multi-round audit

- Normalize path.relative() to forward slashes for Windows compatibility
- Use diff-tree --root for initial commits (git diff --root is invalid)
- Replace String.replace() with indexOf+slice to avoid $& special patterns
- Fix clearAttributions(false→true) when co-author disabled but commit succeeded
- Use real newlines instead of literal \n in PR attribution text
- Add surface fallback in restoreFromSnapshot for version compatibility
- Fix single-quote regex to not assume bash supports \' escaping
- Case-insensitive directory matching in generated file detection
- Handle renamed file brace notation in parseDiffStat

* fix(attribution): also snapshot on ToolResult turns so resume keeps tool edits

Previously, recordAttributionSnapshot() only ran at the start of UserQuery
and Cron turns — before the tools for that turn had executed. A session
that wrote a file in turn 1 and committed in turn 2 (across process
boundaries via --resume) lost the tracked edit: the last persisted
snapshot was the turn-1-start snapshot (empty fileStates), so on resume
the attribution service restored empty state and no git notes were
attached to the commit.

Move the snapshot call out of the UserQuery/Cron conditional and run it
on every non-Retry turn. ToolResult turns are scheduled right after
tools execute, so their start-of-turn snapshot now captures any edits
those tools made. Retry turns are skipped since the state is unchanged
from the prior turn.

Added unit tests asserting the snapshot fires for ToolResult/UserQuery
turns and skips Retry turns.

Verified end-to-end in a scratch repo: write-file in turn 1 (no commit)
→ exit → --resume → commit in turn 2 → git notes now contain the
recorded file with correct aiChars and promptCount: 2.

* refactor(attribution): merge duplicate retry guard and update stale doc

Collapse the two back-to-back messageType !== Retry blocks in
sendMessageStream into one, and refresh chatRecordingService's
recordAttributionSnapshot doc comment to reflect that snapshots fire
on every non-retry turn (not just after user prompts).

* feat(attribution): split gitCoAuthor into independent commit and pr toggles

Matches the shape used upstream in Claude Code's `attribution.{commit,pr}`
so users can disable the PR body line without losing the commit-message
Co-authored-by trailer (or vice versa). The previous boolean forced both
to move together, which conflated two different surfaces.

- settingsSchema: gitCoAuthor becomes an object with nested commit/pr
  booleans, each `showInDialog: true` so both appear in /settings.
- Config constructor accepts legacy boolean (coerced to { commit: v, pr: v })
  so stored preferences from the pre-split schema carry over.
- shell.ts: attachCommitAttribution and addCoAuthorToGitCommit read .commit;
  addAttributionToPR reads .pr.

* feat(settings): add v3→v4 migration for gitCoAuthor shape change

Legacy gitCoAuthor was a single boolean and shipped ~4 months ago; the
previous commit split it into { commit, pr } sub-toggles. Without a
migration, users who had set gitCoAuthor: false would see the settings
dialog show the default (true) for both sub-toggles — misleading and
likely to flip their preference on the next save because getNestedValue
returns undefined when asked for .commit on a boolean.

- New v3-to-v4 migration expands boolean → { commit: v, pr: v },
  preserves already-object values, resets invalid values to {} with a
  warning.
- SETTINGS_VERSION bumped 3 → 4; existing integration assertions use the
  constant so the next bump is a single-line change.
- Regenerate vscode-ide-companion settings.schema.json to reflect the
  new nested shape.
- Docs: split the single gitCoAuthor row into .commit and .pr.

* test(migration): cover null/array/number and partial object for v3-to-v4

The migration already treats any non-boolean, non-object value as invalid
(reset to {} with warning), but the existing test only exercised the
string "yes" branch. Add parameterized cases for null, array, and number
so a future regression that accepts these in the valid bucket gets caught.
Also cover partial objects — the migration must not paternalistically
fill defaults; that responsibility lives in normalizeGitCoAuthor at the
Config boundary.

* fix(shell): address PR review for compound commits and PR body escaping

Two critical issues called out in review:

1. attachCommitAttribution treated the final shell exit code as proof
   that `git commit` itself failed. For compound commands like
   `git commit -m "x" && npm test`, the commit can succeed and a later
   step can fail; the previous code then cleared attribution without
   writing the git note. Now we snapshot HEAD before the command (via
   `git rev-parse HEAD` through child_process.execFile, kept independent
   of the mockable ShellExecutionService) and detect commit creation by
   HEAD movement, so attribution lands whenever a new commit was created
   regardless of later steps.

2. addAttributionToPR spliced the configured generator name into the
   user-approved `gh pr create --body "..."` argument verbatim. A name
   containing `"`, `$`, a backtick, or `'` could break the command or be
   evaluated as command substitution. Now we shell-escape the appended
   text per the surrounding quote style before splicing.

Tests cover the new escape paths for both double- and single-quoted
bodies, including a generator name designed to break interpolation
(`$(rm -rf /) "danger" \`eval\``) and one with an apostrophe.

* fix(attribution): address Copilot review on shell, schema, and totals

Six items called out on PR #3115 by Copilot:

- shell.ts: addAttributionToPR's bash quote escaping doesn't apply to
  cmd.exe / PowerShell, where `\$` and `'\''` aren't honored. Skip the
  PR body rewrite entirely on Windows — losing PR attribution there is
  preferable to corrupting the user-approved `gh pr create` command.

- attributionTrailer.ts + shell.ts call site: buildGitNotesCommand used
  bash-style single-quote escaping on the JSON note, which is broken on
  Windows. Switched to argv form (`{ command, args }`) and routed the
  invocation through child_process.execFile so shell quoting is bypassed
  entirely. Tests updated to assert the argv shape.

- commitAttribution.ts: when a tracked file's aiChars exceeded the diff
  --stat-derived diffSize (long-line edits where diffSize ≈ lines * 40),
  humanChars clamped to 0 but aiChars stayed inflated, leaving aiChars +
  humanChars > the committed change magnitude. Clamp aiChars to diffSize
  so the totals stay consistent.

- shell.ts parseDiffStat: only normalized rename brace notation
  (`{old => new}`). Cross-directory renames emit `old/path => new/path`
  without braces, leaving diffSizes keyed by the full string. Added a
  second normalization step.

- shell.ts: addAttributionToPR docstring claimed `(X% N-shotted)` but
  the implementation only emits `(N-shotted by Generator)`. Updated the
  docstring to match the actual behavior.

- settingsSchema.ts + generator: gitCoAuthor went from boolean to object
  in the V4 migration. The exported JSON Schema now wraps the field in
  `anyOf: [boolean, object]` (via a new `legacyTypes` hint on
  SettingDefinition) so users with a stored boolean don't see a spurious
  IDE warning before their next launch runs the migration.

* fix(attribution): parse binary diffs, source generator from model, sync schema $version

Three follow-up review items from Copilot:

- parseDiffStat now handles git's binary-diff format (`path | Bin A ->
  B bytes`) using the byte delta with a floor of 1. Without this,
  binary edits arrived at the attribution payload as diffSize=0 and
  were silently dropped. Also extracted the parser to a top-level
  exported function so the binary path is unit-testable; added five
  targeted cases (text/binary/rename normalisation/summary skip).

- attachCommitAttribution now passes `this.config.getModel()` into
  generateNotePayload instead of the user-configurable
  `gitCoAuthor.name`. The note's `generator` field reflects which
  model produced the changes — and CommitAttributionService's
  sanitizeModelName() actually has the codename to scrub now.

- generate-settings-schema.ts imports SETTINGS_VERSION instead of
  hardcoding `default: 3`, so a future bump propagates to the emitted
  JSON schema in one place. Regenerated settings.schema.json bumps
  $version's default from 3 to 4 to match the V4 migration.

* fix(attribution): repo-root baseDir, escape co-author trailer, switch to numstat

Three Critical items called out by wenshao:

- attachCommitAttribution was passing config.getTargetDir() as `baseDir`
  to generateNotePayload, but getCommittedFileInfo returns paths
  relative to `git rev-parse --show-toplevel`. When the working
  directory was a subdirectory of the repo, path.relative produced
  `../...` keys that never matched in the AI-attribution lookup,
  silently zeroing out attribution for every file outside getTargetDir.
  StagedFileInfo now carries an optional `repoRoot` (filled in by
  getCommittedFileInfo via `git rev-parse --show-toplevel`) and the
  caller prefers it over the target dir.

- addCoAuthorToGitCommit interpolated `gitCoAuthorSettings.name` and
  `.email` into the rewritten command without escaping. A name
  containing `$()`, backticks, or `"` could be evaluated as command
  substitution under double quotes, or break the user-approved
  `git commit -m "..."` quoting. Now escapes per the surrounding quote
  style with the same helpers addAttributionToPR uses, gates on
  non-Windows for the same shell-quoting reason, and fixes the regex
  to accept `-m"msg"` shorthand (no space) so users who type the
  bash-shorthand form aren't silently denied a trailer.

- parseDiffStat used `git diff --stat` output and approximated each
  line as ~40 chars by parsing a graphical text bar. Replaced with
  `git diff --numstat` which gives unambiguous integer
  additions+deletions per file; the heuristic remains but the parser
  is no longer fooled by the visual `++--` markers. Binary entries
  fall back to a fixed estimate so they still land in the map (rather
  than dropping out as diffSize=0).

Suggestions also addressed: stale duplicate JSDoc on
addCoAuthorToGitCommit removed, misleading `clearAttributions`
comments rewritten to describe what the boolean argument actually
does. Tests cover the new shorthand path, escape behavior, and
numstat parsing (text/binary/rename/malformed).

* fix(shell): shell-aware git-commit detection and apostrophe-escape handling

Two more Critical items called out by wenshao plus the matching Copilot
quote-handling notes:

- attachCommitAttribution and addCoAuthorToGitCommit now go through a
  shell-aware `looksLikeGitCommit` helper instead of a raw
  `\bgit\s+commit\b` regex. The helper splits the command on shell
  separators (`splitCommands`) and checks each segment, so `echo "git
  commit"` no longer triggers attribution clearing or trailer
  injection. The same helper bails on any segment that contains `cd`
  or `git -C <path>`, since either could redirect the commit into a
  different repo than our cwd — writing notes or capturing HEAD there
  would corrupt unrelated state.

- The post-command attribution call now runs regardless of whether the
  shell wrapper aborted. `git commit -m "x" && sleep 999` could move
  HEAD and then time out, leaving the new commit without its
  attribution note while the stale per-file attribution stayed around
  for a later unrelated commit. attachCommitAttribution still gates on
  HEAD movement, so it's a no-op when no commit was actually created.

- The `-m '...'` and `--body '...'` regexes used to match only the
  first quote segment, so a command like `git commit -m 'don'\''t'`
  (bash's standard apostrophe-escape form) would have the trailer
  spliced mid-message and break the command's quoting. The single-
  quote patterns now use a negative lookahead / inner alternation to
  either skip those messages entirely (commit path) or match the
  whole escape-aware body (PR path).

Tests cover the new behavior: quoted "git commit" is left alone, the
`cd && git commit` and `git -C` patterns get no trailer, and the
apostrophe-escape form passes through unchanged for both `-m` and
`--body`.

* fix(attribution): drop magic 100 fallback for empty deletions

Deleted files with no AI tracking now use diffSize directly. With
numstat as the input source, diffSize is an exact count, and an
empty-file deletion legitimately reports zero — a magic fallback would
only inflate totals.

* fix(shell): broaden git-commit detection, gate background, drop dead helpers

Five Copilot follow-ups:

- looksLikeGitCommit now strips leading env-var assignments
  (`GIT_COMMITTER_DATE=now git commit ...`) and a small allowlist of
  safe wrappers (`sudo`, `command`) before matching. The previous
  exact-prefix match silently skipped trailer injection on common
  real-world commit forms.

- A new looksLikeGhPrCreate (same shell-aware shape) replaces the raw
  `\bgh\s+pr\s+create\b` regex in addAttributionToPR, so quoted text
  like `echo "gh pr create --body \"x\""` no longer triggers a
  command-string rewrite.

- executeBackground refuses to run `git commit` and tells the user to
  re-run foreground. The BackgroundShellRegistry lifecycle has no
  hook for the post-command pre/post-HEAD comparison or git-notes
  write, so allowing the commit through would create the new commit
  without notes and leak stale per-file attribution into the next
  foreground commit.

- recordDeletion was unused outside its own test — removed (and the
  test). When AI-driven deletions need tracking we'll add it with an
  actual integration point rather than carrying dead API surface.

- generatePRAttribution was likewise unused; addAttributionToPR
  builds the trailer string inline. The two formats had already
  diverged. Removed the helper and its tests; reviving from git
  history is straightforward if a future caller needs it.

Tests: env-var and sudo prefixes now produce trailers; quoted
"gh pr create" leaves the command unchanged; existing 81 shell tests
still pass alongside the trimmed 25 commitAttribution tests.

* fix(shell): unified git-commit detection split by intent

Six items called out across CodeQL, Copilot, and wenshao:

- The earlier `looksLikeGitCommit`/`stripCommandPrefix` returned a
  single yes/no and rejected ANY `cd` in the chain. That fixed the
  wrong-repo case but also disabled attribution for `git commit -m
  "x" && cd ..` (commit already landed safely in our cwd; the cd
  came after). It also conflated three distinct decisions onto one
  predicate.

  New `gitCommitContext` returns both `hasCommit` and
  `attributableInCwd`, walking segments in order so that a `cd`
  AFTER the commit doesn't invalidate it. Callers now pick the right
  arm:
  - background-mode refusal uses `hasCommit` (refuses even
    `cd /elsewhere && git commit` since we can't attribute it
    afterward either way)
  - HEAD snapshot, addCoAuthorToGitCommit, and the
    attachCommitAttribution gate use `attributableInCwd`

- Tokenisation switches from a regex while-loop to `shell-quote`'s
  `parse`. Quoted env values like `FOO="a b" git commit` now skip
  correctly (the old `\S*\s+` form would cut after the opening
  quote). Eliminates the CodeQL polynomial-regex alert at the same
  time since the `\S*\s+` pattern is gone.

- attachCommitAttribution now snapshots prompt counters via
  `clearAttributions(true)` whenever a commit lands, even if no
  per-file attributions were tracked. Previously the early-return
  on `hasAttributions() === false` meant `promptCountAtLastCommit`
  never advanced, so a later `gh pr create` reported an inflated
  N-shotted count spanning multiple commits.

Tests: env-var and sudo prefixes still produce trailers; quoted
"git commit" / "gh pr create" leave commands unchanged; cd BEFORE
commit suppresses the rewrite while cd AFTER commit does not; `git
-C <path> commit` is treated as a commit (refused in background)
but not as attributable.

* fix(shell): position-independent git subcommand detection + bash-shell guard

Six review items, two of them critical:

- gitCommitContext was checking fixed-position tokens (`arg1`, `arg3`)
  and missed every git invocation that puts a global flag between
  `git` and the subcommand: `git -c user.email=x@y commit`,
  `git --no-pager commit`, `git -C /p -c k=v commit`, etc. In
  background mode these would slip past the refusal guard; in
  foreground they got no co-author trailer, no git note, and no
  prompt-counter snapshot. New `parseGitInvocation` walks past
  git's global flags (with their values) before reading the
  subcommand, and reports `changesCwd` for `-C` / `--git-dir` /
  `--work-tree`.

- The Windows guard on addCoAuthorToGitCommit and addAttributionToPR
  used `os.platform() === 'win32'`, which incorrectly skipped Windows
  + Git Bash (`getShellConfiguration().shell === 'bash'`). Switched
  both to gate on `getShellConfiguration().shell !== 'bash'` so Git
  Bash users keep the feature.

- attachCommitAttribution was re-parsing `gitCommitContext(command)`
  even though `execute()` already gates on `commitCtx.attributableInCwd`.
  Removed the redundant re-parse — drift between the two checks would
  silently diverge trailer injection from git-notes writes.

- tokeniseSegment (formerly tokeniseProgram) now logs via debugLogger
  on parse failure instead of swallowing silently. Easier to debug
  if shell-quote ever throws on something unusual.

- Added a comment on `cwdShifted` documenting that it's a one-way
  latch — `cd src && cd ..` will still skip attribution. The
  trade-off matches the wrong-repo guard's "better miss than corrupt
  unrelated repos" intent.

- Stale `--stat` reference in the aiChars-clamp comment updated to
  `--numstat` to match the actual git command in
  ShellToolInvocation.getCommittedFileInfo.

Tests: `git -c key=val commit` and `git --no-pager commit` now
produce a trailer; existing 82 shell tests still pass.

* fix(shell): refuse multi-commit attribution; misc review follow-ups

Five follow-ups from the latest review pass:

- attachCommitAttribution now refuses to write a single git note for
  shell commands that produce more than one commit (e.g.
  `git commit -m a && git commit -m b`). The singleton's per-file
  attribution map can't be partitioned across the individual commits,
  so attaching the combined note to HEAD would mis-attribute earlier
  commits' changes to the last one. Walks `preHead..HEAD` via
  `git rev-list --count`; on multi-commit detection it snapshots the
  prompt counters and bails with a debug warning instead of writing
  a misleading note.

- parseGitInvocation now recognises the attached `-C/path` form
  (e.g. `git -C/path commit -m x`). shell-quote tokenises that as a
  single `-C/path` token which previously fell to the generic flag
  branch with `changesCwd = false`, leaving an out-of-cwd commit
  classified as attributable.

- attachCommitAttribution dropped its unused `command` parameter
  (the caller already gates on `commitCtx.attributableInCwd`, so
  re-parsing was removed earlier; the parameter became dead).

- Added wiring guards in edit.test.ts and write-file.test.ts:
  AI-originated edits/writes hit `CommitAttributionService.recordEdit`,
  `modified_by_user: true` skips, and write-file's distinction
  between a true new file and an overwritten empty file (`null` vs
  `''` old content) is now pinned by `aiCreated` assertions.

* fix(attribution): partial-commit clear, symlink baseDir, gh/git flag handling

Two Critical items, two Copilot, and five wenshao Suggestions:

- attachCommitAttribution's `finally` block used to call
  `clearAttributions()` unconditionally, wiping per-file tracking
  for files the AI had edited but the user excluded from this
  commit. Added `clearAttributedFiles(committedAbsolutePaths)` to
  the service and the call site now passes only the paths that
  actually landed in this commit; entries for un-`add`ed files stay
  pending for a later commit.

- generateNotePayload now runs both `baseDir` and each tracked
  absolute path through `fs.realpathSync` before `path.relative`.
  On macOS in particular `/var` symlinks to `/private/var`, so the
  toplevel from `git rev-parse --show-toplevel` and the absolute
  path captured by edit/write-file tools could diverge — producing
  `../../actual/path` keys in the lookup that never matched and
  silently zeroed all per-file AI attribution.

- tokeniseSegment now consumes value-taking sudo flags (`-u`,
  `-g`, `-h`, `-D`, `-r`, `-t`, `-C`, plus the long forms). Without
  this, `sudo -u other git commit` left `other` standing in for
  the program name and skipped the trailer entirely.

- A duplicate JSDoc block above `countCommitsAfter` (a leftover
  from the earlier extraction of `getGitHead`) was removed; both
  helpers now have one accurate comment each.

- attachCommitAttribution's multi-commit guard now also runs when
  `preHead === null` (brand-new repo), via `git rev-list --count
  HEAD`. A compound `git init && git commit -m a && git commit -m b`
  no longer slips through and mis-attributes combined data to the
  last commit.

- addCoAuthorToGitCommit's `-m` matching switched to `matchAll` and
  takes the LAST match. `git commit -m "title" -m "body"` puts the
  trailer at the end of the body so `git interpret-trailers`
  recognises it; the previous first-match behaviour stuffed the
  trailer in the title where git treats it as plain message text.

- addAttributionToPR's `--body` regex accepts both space and
  `=` separators (`--body "..."` and `--body="..."`); the `=` form
  is common with gh.

- New `parseGhInvocation` walks past gh's global flags
  (`--repo`, `-R`, `--hostname`) so `gh --repo owner/repo pr
  create ...` is detected. The earlier fixed-position check at
  tokens[1]/tokens[2] missed any command with a global flag.

- getCommittedFileInfo now fans out the two `rev-parse` calls and
  the three diff calls with `Promise.all`. They're independent and
  serialising them was paying spawn latency 5× per commit.

Tests: sudo with `-u user`, multi `-m`, `gh --repo owner/repo`,
`--body="..."`, plus the existing 84 shell tests still pass.

* fix(attribution): canonicalize file paths centrally in CommitAttributionService

Two related Copilot follow-ups:

- recordEdit/getFileAttribution/clearAttributedFiles now run input
  paths through fs.realpathSync before storing/looking up, so a
  symlinked path (e.g. macOS /var ↔ /private/var) resolves to the
  same key regardless of which form the caller passes. Previously
  edit.ts/write-file.ts handed in non-realpath'd absolute paths
  while generateNotePayload tried to realpath only inside its
  lookup loop, leaving partial-clear and clear-on-finally paths
  unable to find entries when the forms diverged.

- restoreFromSnapshot also canonicalises on the way in so a
  session resumed from a pre-fix snapshot (where keys may not
  have been canonical) ends up with the same shape as newly
  recorded entries — otherwise a single file could end up with
  two parallel records.

- generateNotePayload's lookup loop dropped its per-entry realpath
  call (now redundant since keys are canonical at write time),
  keeping only the realpath of `baseDir` (which still comes from
  `git rev-parse --show-toplevel` and may be a symlink).

- Updated `clearAttributedFiles` doc to describe the new semantics:
  callers can pass either the resolved repo-relative path or an
  already-canonical absolute path, and either will match.

* fix(attribution): canonicalize-from-root cleanup; fix mixed-quote -m / gh -R=

Five review items, one Critical:

- attachCommitAttribution now canonicalises via the repo *root* (one
  realpath call) and resolves committed paths against that canonical
  root, rather than per-leaf realpath inside clearAttributedFiles.
  At cleanup time the leaf for a just-deleted file no longer exists,
  so per-leaf fs.realpathSync would fail and silently fall back to a
  non-canonical path that misses the stored canonical key — leaving
  stale attributions for deleted files.
  clearAttributedFiles drops its internal realpath and now documents
  the canonical-paths-required precondition explicitly.

- addCoAuthorToGitCommit picks the LAST `-m` regardless of quote
  style. Previously `doubleMatch ?? singleMatch` always preferred
  the last double-quoted match, so `git commit -m "Title" -m
  'Body'` injected the trailer into the title where git
  interpret-trailers would silently ignore it. Now compares match
  indices, and the escape helper follows the actually-selected
  match's quote style.

- parseGhInvocation handles `-R=value` (the equals form of the
  short `--repo` alias). `--repo=...` and `--hostname=...` were
  already covered; `-R=...` previously fell through to the generic
  flag branch and skipped the value.

- New tests for the symlink-aware canonicalisation: macOS-style
  `/var` ↔ `/private/var` mapping is mocked via vi.mock on
  node:fs, with cases for record-then-look-up under either form,
  generateNotePayload with a symlinked baseDir, partial clear via
  the canonical-root-derived path (deleted leaf), and snapshot
  restore canonicalisation.

- Doc-only: integration-test header comments updated from
  "V1 -> V2 -> V3" / "migration to V3" to reflect the actual V4
  end state (assertions already used the literal `4`).

* fix(shell): scope -m rewrite to commit segment, reject nested matches

Two Critical findings on addCoAuthorToGitCommit, plus a Copilot
maintainability nit:

- The `-m` regex used to scan the whole compound command, so
  `git commit -m "fix" && git tag -a v1 -m "release"` would target
  the LATER tag annotation (last -m wins) and splice the trailer
  there instead of the commit message. The rewrite now scopes to
  the actual `git commit` segment via a new
  findAttributableCommitSegment(): same shell-aware walk
  gitCommitContext does, but returning the segment's character
  range so the regex can be run on a slice and spliced back into
  the original command.

- Within the segment, a literal `-m '...'` *inside* a quoted body
  was treated as a real later -m. For
  `git commit -m "docs mention -m 'flag' for completeness"`, the
  inner single-quoted -m sits at a higher index than the real
  outer -m, and the previous index comparison would have it win —
  splicing the trailer mid-message and corrupting the quoting.
  The new code checks whether the candidate is nested inside the
  other quote-style's range (start/end containment) and prefers
  the outer match when so.

- Hoisted three constant Sets (sudo flag list, git global flags
  taking values, git global flags shifting cwd, gh global flags)
  out of the per-call scope to module constants. Functional
  no-op, but keeps the parsing helpers easier to read and avoids
  re-allocating the Sets on every command.

Two regression tests added for the cases above:
- inner `-m '...'` inside the outer message body is preserved
  literally and the trailer lands after the body
- `git tag -a v1 -m "release notes"` after a real
  `git commit -m "fix"` is left untouched, with the trailer
  appended to "fix" only

* fix(attribution): cd-leak, numstat partial failure, $() bailout, gh pr new alias

Five Critical/Suggestion items:

- `cd subdir && git commit` (or any non-attributable commit chain
  whose HEAD movement still happens in our cwd, e.g. cd into a
  subdirectory of the same repo) used to skip attribution AND fail
  to clear pending per-file entries. Those entries then leaked into
  the next foreground commit, inflating its AI percentage. New
  `else if (commitCtx.hasCommit)` branch in execute() compares pre-
  and post-HEAD; if HEAD moved we drop the per-file state. preHead
  is now snapshotted whenever ANY commit was attempted, not only
  attributable ones.

- getCommittedFileInfo's three diff calls run in `Promise.all`. If
  `--numstat` failed while `--name-only` succeeded, every file's
  diffSize would be 0 and generateNotePayload would clamp aiChars
  to 0 — emitting a structurally valid note with all-zero AI
  percentages. Detect the partial-failure shape (files non-empty,
  diffSizes empty) and return empty so no note is written.

- addCoAuthorToGitCommit and addAttributionToPR now bail when the
  captured `-m`/`--body` value contains `$(`. The tool description
  recommends `git commit -m "$(cat <<'EOF' ... EOF)"` for
  multi-line messages, but the regex's `(?:[^"\\]|\\.)*` body group
  stops at the first interior `"` from a nested shell token —
  splicing the trailer there breaks the command before it reaches
  the executor.

- looksLikeGhPrCreate now accepts `gh pr new` as well — it's a
  documented alias for `gh pr create` and was silently skipped.

- Removed `incrementPermissionPromptCount` / `incrementEscapeCount`
  and their getters: they had no production callers, so the backing
  fields just round-tripped through snapshots as 0. The four
  snapshot fields are now optional so pre-fix snapshots that carry
  non-zero values still load cleanly and just get ignored.

Three regression tests added: heredoc-style `-m "$(cat <<EOF...)"`
preserved literally, heredoc-style `--body` likewise, `gh pr new
--body "..."` rewritten with attribution.

* fix(attribution): --amend, --message/-b aliases, .d.ts over-exclusion

Four Copilot follow-ups, three of them user-visible coverage gaps:

- `git commit --amend` was diffing `HEAD~1..HEAD` for attribution,
  which spans the entire amended commit (parent → amended) rather
  than the actual amend delta. A message-only amend would emit a
  note attributing every file in the original commit to this
  amend. New `isAmendCommit` helper detects the flag and
  getCommittedFileInfo switches to `HEAD@{1}..HEAD` (the pre-amend
  HEAD vs the amended HEAD); if the reflog is GC'd we bail with a
  warning rather than over-attribute.

- `git commit --message "..."` and `--message="..."` were silently
  skipped because the regex only recognised the short `-m` form.
  The flag prefix now matches both alternatives via
  `(?:-[a-zA-Z]*m|--message)\s*=?\s*` (non-capturing inner group
  so the existing `[full, prefix, body]` destructure still works).

- `gh pr create -b "..."` (the short alias for `--body`) was the
  same gap on the PR side; `(?:--body|-b)[\s=]+` now covers both
  forms.

- `.d.ts` was an over-broad blanket exclusion in
  EXCLUDED_EXTENSIONS — declaration files are commonly authored
  (ambient declarations, asset shims like `*.d.ts` for
  `import './x.svg'`); the repo even contains
  `packages/vscode-ide-companion/src/assets.d.ts`. Removed `.d.ts`
  from the extensions Set and adjusted the test to assert the new
  behavior. Auto-generated `.d.ts` (e.g. `tsc --declaration`
  output) still gets caught by the build-directory rules.

Tests added: `--amend` plumbing covered by the new branch in
getCommittedFileInfo (no targeted unit test — the diff invocation
goes through ShellExecutionService and is exercised by the existing
post-command path); `--message`/`--message="..."`/-b/-b="..."` all
have positive trailer-injection assertions; `.d.ts` test split into
"hand-authored" (negative) and "in dist" (positive).

* fix(attribution): cd-subdir, scope --body, multi-commit count guard, /clear reset

Four bugs flagged this round:

- gitCommitContext / findAttributableCommitSegment used a blanket
  "any cd shifts cwd" gate, breaking the very common
  `cd subdir && git commit -m "..."` flow even though the commit
  lands in the same repo. New `cdTargetMayChangeRepo` heuristic:
  treat relative paths that don't escape upward (no leading `..`,
  no absolute path, no `~`/`$VAR` expansion, no bare `cd`/`cd -`)
  as in-repo and let attribution proceed. Conservative on anything
  it can't statically verify.

- addAttributionToPR was running the `--body`/`-b` regex against
  the FULL compound command string. In
  `curl -b "session=abc" && gh pr create --body "summary"` the
  regex would match curl's `-b` cookie flag and inject attribution
  into the cookie value, corrupting the curl call. Added
  `findGhPrCreateSegment` (analog of `findAttributableCommitSegment`)
  and scoped the body regex to that segment, splicing back into
  the original command via offsetting the in-segment match index.

- The multi-commit guard treated `runGitCount === 0` as "single
  commit" and bypassed itself. After `commitCreated === true`, a
  count of 0 is impossible in normal operation — it means
  rev-list errored or timed out. Now we bail on `commitCount !== 1`
  with a tailored message: anything other than exactly 1 commit
  is suspicious and refuses the note.

- The CommitAttributionService singleton survives across
  `Config.startNewSession()` (the `/clear` and resume paths). New
  `CommitAttributionService.resetInstance()` call alongside the
  existing chat-recording / file-cache resets in startNewSession
  prevents pending attributions from a prior session attaching to
  a commit in the new one.

Three regression tests added: `cd src && git commit` produces a
trailer (in-repo cd), `cd .. && git commit` does not (could escape
repo root), and `curl -b "..." && gh pr create --body "..."` leaves
curl's cookie value untouched while attribution lands in gh's body.

* fix(attribution): cd embedded .., env wrapper, Windows ARG_MAX, segment-locator warn

Four review items, all small but real:

- cdTargetMayChangeRepo missed embedded `..` traversal — `cd
  foo/../../escape` and similar would slip past the leading-`..`
  check and be treated as in-repo. Added an `includes('/..')` /
  `includes('\\..')` check (catches POSIX and Windows separators
  without false-positiving on `..` chars inside ordinary names,
  which only escape when followed by a separator).

- tokeniseSegment now recognises `env` as a safe wrapper alongside
  `sudo`/`command`, so `env GIT_COMMITTER_DATE=now git commit ...`
  resolves to `git`. After the wrapper detection we also skip any
  `KEY=VALUE` argv entries (env's own argument syntax for setting
  vars before the program).

- buildGitNotesCommand's MAX_NOTE_BYTES dropped from 128 KB to
  30 KB. Windows' CreateProcess lpCommandLine is capped around
  32,768 UTF-16 chars including the executable path and other argv
  entries; a 128 KB note would still fail to spawn even though
  the function returned a command instead of null. 30 KB leaves
  ~2 KB of headroom for the rest of the argv on Windows and is
  larger than any real commit's metadata in practice.

- findAttributableCommitSegment / findGhPrCreateSegment now log a
  debugLogger.warn when `command.indexOf(sub, cursor)` returns -1
  — splitCommands strips line continuations (`\<newline>`), so a
  multi-line command can have the trimmed segment text fail to
  match its source. Previously the segment was silently skipped
  with no signal; the warn makes the failure observable when
  QWEN_DEBUG_LOG_FILE is set.

Two regression tests added: `cd foo/../../escape && git commit`
gets no trailer (embedded-`..` heuristic catches it), and
`env GIT_COMMITTER_DATE=now git commit` does (env wrapper skipped).

* fix(attribution): scope isAmendCommit to attributable segment only

`git -C ../other commit --amend && git commit -m x` would previously
flag the second (fresh) commit as an amend, causing
attachCommitAttribution to diff `HEAD@{1}..HEAD` against an unrelated
reflog entry. Mirror findAttributableCommitSegment's cd/cwd tracking
so only the first commit segment that runs in the original cwd
determines amend status.

* fix(attribution): last-match --body, symlink leaf canonicalisation, scoped prompt count

- addAttributionToPR: use matchAll/last-match for `--body`/`-b` so the
  trailer lands in the gh-honoured (final) body when multiple flags are
  present. Mirrors addCoAuthorToGitCommit. Adds regression test.
- attachCommitAttribution: also fs.realpathSync the per-file resolved
  path (not just the repo root) so files behind intermediate symlinks
  are matched against canonical keys recordEdit stored, instead of
  silently zeroing attribution and leaking entries past commit.
- incrementPromptCount: scope to SendMessageType.UserQuery — ToolResult,
  Retry, Hook, Cron, Notification are model/background re-entries of
  the same logical turn. Tracking them all inflated the "N-shotted"
  trailer (one user message could become 10-shotted with 10 tool calls).
- AttributionSnapshot: add `version: 1` field; restoreFromSnapshot now
  refuses incompatible versions and validates per-field types so a
  partially-written snapshot can't seed `Math.min(undefined, n) === NaN`
  into git-notes payloads.
- Drop unused permission/escape counters (declared, persisted, never
  read or incremented) — fields, snapshot tolerance, and clear-method
  bookkeeping all removed; AttributionSnapshot interface simplifies.
- isGeneratedFile: switch directory rule from substring `.includes('/dist/')`
  to segment-boundary check (split on `/`) so project dirs like
  `my-dist/` or `xbuild/` don't match. `.lock` removed from the blanket
  extension exclusion — well-known lockfiles already covered by
  EXCLUDED_FILENAMES; hand-authored `.lock` files (e.g. `.terraform.lock.hcl`)
  now stay attributable.
- getClientSurface: document `QWEN_CODE_ENTRYPOINT` as the embedder
  override hook so the always-`'cli'` default is intentional.

* fix(attribution): skip values for env -u NAME and -S string

`env`'s value-taking flags (`-u`/`--unset`, `-S`/`--split-string`) were
not in the wrapper's flag-skip allowlist, so `env -u FOO git commit ...`
left FOO as the next token and the parser treated it as the program —
masking the real `git commit` from attribution detection. Add an
ENV_FLAGS_WITH_VALUE table mirroring the sudo allowlist. Regression
test added.

* fix(attribution): submodule leak, PR body nesting, shallow-clone bail, schema default

- attachCommitAttribution: when HEAD didn't move in our cwd, leave
  pending attributions alone instead of dropping them. The case can be
  a failed commit, `git reset HEAD~1`, OR `cd submodule && git commit`
  (inner repo's HEAD moves, ours doesn't). Dropping was overly
  aggressive and silently lost outer-repo edits in the submodule case.
- addAttributionToPR: mirror addCoAuthorToGitCommit's nested-match
  rejection so `gh pr create --body "docs mention -b 'flag'"` picks the
  outer `--body`, not the inner literal `-b`. Splicing into the inner
  match would corrupt the body. Regression test added.
- getCommittedFileInfo: when `rev-parse --verify HEAD~1` fails, also
  check `rev-list --count HEAD === 1` to confirm HEAD is the true
  root commit. In a shallow clone, HEAD~1 is unreadable but the commit
  has a parent recorded — falling back to `diff-tree --root` would
  diff against the empty tree and over-attribute the entire commit.
  Bail with a debug warning instead.
- generate-settings-schema: lift `default` (and `description`) out of
  the inner `anyOf[N]` schema to the outer level when wrapping with
  `legacyTypes`. Most JSON-schema-driven editors only surface
  top-level defaults; burying the default under `anyOf` lost the
  "enabled by default" hint. Also extend the default filter to
  publish non-empty plain objects (so `gitCoAuthor`'s default can
  appear). gitCoAuthor's source default updated to the runtime shape
  `{commit: true, pr: true}` to match `normalizeGitCoAuthor`.

* fix(attribution): drop unsafe full-clear, tag analysis-failure with null

ju1p (Copilot): the `else if (commitCtx.hasCommit)` branch fully
cleared the singleton on `cd /abs/same-repo/subdir && git commit`
(or `git -C . commit`), losing pending AI edits the user hadn't
staged. We can't tell which files were in the commit from this
branch, and the next attributable commit's partial-clear handles
cleanup correctly anyway. Drop the branch entirely.

ju2D (Copilot): `getCommittedFileInfo` returned the same empty
StagedFileInfo for both "could not analyze" (shallow clone, --amend
without reflog, --numstat partial failure, exception) and
"intentionally empty" (--allow-empty). The caller couldn't tell them
apart, so the partial clear became a no-op on analysis failure and
the just-committed AI edits leaked to the next commit. Switch the
return type to `StagedFileInfo | null` and have the caller treat
null as "fall back to full clear" while empty StagedFileInfo
(--allow-empty) leaves attributions intact for the next real commit.

* fix(attribution): dedup snapshot writes, cap excludedGenerated, doc commit toggle scope

rsf- (Copilot): recordAttributionSnapshot wrote a full snapshot to
the JSONL on every non-retry turn, even when the tracked state was
unchanged. Long-running sessions accumulated thousands of identical
snapshot copies, inflating session size and slowing /resume hydrate.
Dedup by JSON-equality with the prior write — first write always
goes through, identical successors are no-ops.

rsgo (Copilot): excludedGenerated path list was unbounded. A commit
churning thousands of generated artifacts (large dist/ rebuild)
could push the JSON note past MAX_NOTE_BYTES (30KB) and lose
attribution for the real source files in the same commit. Cap the
serialized sample at MAX_EXCLUDED_GENERATED_SAMPLE (50) and add
excludedGeneratedCount for the true total.

rsg9 + rshM (Copilot): the gitCoAuthor.commit description claimed
the toggle only controlled the Co-authored-by trailer, but
attachCommitAttribution also gates the per-file git-notes payload
on the same flag. Update both the schema description and the
settings.md table to mention both effects so disabling the option
isn't a silent surprise.

* fix(attribution): depth-1 shallow detection, snapshot dedup post-rewind/post-failure

sfGz (Copilot): rev-list --count HEAD === 1 cannot distinguish a
true root commit from a depth-1 shallow clone — both report 1
because rev-list only walks locally available objects. Switch to
git log -1 --pretty=%P HEAD which reads the parent SHA directly
from commit metadata: empty means a real root, non-empty means a
parent is recorded (whether or not its object is local). The
shallow-clone bail is now reliable.

sfIm (Copilot): the dedup key persisted across rewindRecording, so
the previous snapshot living on the now-abandoned branch would
match the next post-rewind snapshot and silently skip the write,
leaving /resume on the rewound session with no attribution state.
Reset lastAttributionSnapshotJson when rewindRecording fires.

sfJE (Copilot): dedup key was committed before the async write
settled. A transient write failure would update the key, then
permanently suppress all future identical snapshots even though
nothing was ever persisted. Switch to optimistic-set then rollback
on appendRecord rejection — synchronous identical calls dedup
cleanly, but a failed write clears the key so the next identical
snapshot retries. appendRecord now returns the per-record write
promise (writeChain still has its swallow-catch for chain liveness)
so callers needing per-write success can react to it. Tests added
in chatRecordingService.test.ts for both rewind-reset and
rollback-on-failure paths.

* fix(attribution): preHead race, regex apostrophe-escape, surface failures, dead code

t2G0 (deepseek-v4-pro): addCoAuthorToGitCommit single-quote regex now
matches the bash close-escape-reopen apostrophe form using
((?:[^']|'\\'')*) — the same pattern bodySinglePattern uses for
gh pr create. Input like git commit -m 'don'\''t' was previously
silently un-rewritten because the negative lookahead bailed; the
trailer now lands at the FINAL closing quote. Test updated.

tMBP (gpt-5.5): preHead capture switched from concurrent async
getGitHead to a synchronous getGitHeadSync (execFileSync) BEFORE
ShellExecutionService.execute spawns the user's command. A fast
hot-cached git commit could move HEAD before the async rev-parse
resolved, leaving preHead === postHead and silently skipping the
attribution note. Trade ~10–50 ms event-loop block per
commit-shaped command for correctness of the post-command HEAD
comparison.

t2Gv (deepseek-v4-pro): attribution write failures (note exec
non-zero, payload too large, diff-analysis exception, shallow
clone / amend-without-reflog) are now surfaced on the shell tool's
returnDisplay AND llmContent so the user and agent both see when
their commit succeeded but the per-file git note didn't land.
attachCommitAttribution now returns string | null (warning text or
null for intentional skips like no-tracked-edits). Co-authored-by
trailer is unaffected — only the note is gated by these failures.

t2Gy (deepseek-v4-pro): committedAbsolutePaths now matches against
the canonical keys already stored in fileAttributions
(matchCommittedFiles iterates by relative path against the
canonical repo root) instead of re-resolving each diff path
on the fly. realpathSync(resolved) failed for deleted files and
didn't follow intermediate symlinks, leaving stale per-file
attribution alive past commit and inflating AI percentages on
subsequent commits.

t2HI (deepseek-v4-pro): removed dead sessionBaselines /
FileBaseline / contentHash / computeContentHash infrastructure
(~40 lines). The fields were written, persisted, and restored but
never read for any computation or decision. AttributionSnapshot
schema stays at version 1 — restore tolerates pre-fix snapshots
that carried the now-ignored baselines field.

t2HM (deepseek-v4-pro): extracted the duplicated lastMatch helper
in addCoAuthorToGitCommit and addAttributionToPR into a single
module-level lastMatchOf so future fixes can't be applied to only
one copy.

* chore(schema): regenerate settings.schema.json to match gitCoAuthor.commit description

The settingsSchema.ts source for `gitCoAuthor.commit.description` was
updated in 3c0e3293b but the JSON schema only picked up the OUTER
description rewrite and missed this inner property's. The Lint check
("Check settings schema is up-to-date") fails on that drift; this
commit re-runs `npm run generate:settings-schema` to sync them.

* fix(attribution): preserve unstaged AI edits across cleanup branches

uxU5 + uxVQ + uxUO (Copilot): every cleanup branch in
attachCommitAttribution that called clearAttributions(true) was
wholesale-erasing pending AI edits for files the user never staged
in this commit. Reviewer scenarios:
- multi-commit chain (`commit a && commit b`) bails out without
  writing a note, but unstaged edits to file Z (touched by neither
  commit) get cleared along with the chain's committed files.
- attribution toggle off: same — toggling the flag wipes pending
  unstaged work.
- analysis failure (shallow clone, --amend without reflog, partial
  diff failure): the finally-block fallback wholesale-cleared
  every pending file, consuming unrelated AI edits.
- 0%-AI commit: when no file in the commit was AI-touched,
  generateNotePayload was emitting an "0% AI" note attached to a
  commit that legitimately had no AI involvement — actively
  misleading metadata.

Add `noteCommitWithoutClearing()` to the service: snapshots the
prompt counter as the new "at last commit" but leaves the per-file
map alone. Use it in the multi-commit, no-tracked-edits,
toggle-off, and analysis-failure paths. The committed-files
partial-clear (clearAttributedFiles) still runs in the success
path. The 0%-AI no-match case now skips the note write entirely.

* fix(attribution): runGit null-on-failure, versionless v3→v4 migration

z54M (Copilot): runGit returned '' on both successful-empty-output
and silent failure, so a `--name-only` that errored mid-way through
the diff fan-out aliased to a real `--allow-empty` commit. The
empty-commit branch then preserved pending attributions, leaving
the just-committed file's tracked AI edit alive to re-attribute on
the next commit. Switch runGit to `Promise<string | null>`,
distinguishing exit code 0 (any output, including '') from non-zero
(null). The diff-stage fan-out and ancillary probes now treat null
as analysis failure and bail with `return null` instead of falling
into the empty-commit path.

z539 (Copilot): the v3→v4 `shouldMigrate` only fired on
`$version === 3`. A versionless settings file carrying the legacy
`general.gitCoAuthor: false` boolean would skip every migration
(gitCoAuthor isn't in V1_INDICATOR_KEYS — it post-dates V2), get
its `$version` normalized to 4 by the loader, and leave the
boolean in place. The settings dialog then reads the V4
`{commit, pr}` shape, sees missing keys, defaults both to true, and
silently overwrites the user's opt-out on the next save. Also fire
when `$version` is absent AND the value at `general.gitCoAuthor`
is a boolean. Tests cover the new path and confirm the existing
versioned/object-shape paths are untouched.

* fix(attribution): toggle-off partial clear, normalizeGitCoAuthor type-check, terraform lockfile

0oAK (Copilot): the gitCoAuthor.commit toggle-off branch returned
before computing the committed file set, leaving the just-committed
files' tracked AI work in the singleton. Re-enabling the toggle and
committing the same file again would re-attribute earlier (already-
committed) AI edits to the new commit. Move the toggle gate AFTER
matchCommittedFiles so the finally block does a proper partial clear
of the just-committed files even when the note write is skipped.

0oAg (Copilot): normalizeGitCoAuthor copied value?.commit / value?.pr
without type-checking. settings.json is hand-editable; a stored
`{ commit: "false" }` reached runtime as a truthy string and behaved
as if attribution were enabled. Add a per-field bool coercion that
falls back to the schema default (true) for any non-boolean,
matching what the dialog and IDE schema already imply. Tests cover
the string / number / null cases.

0oAo (Copilot): v3→v4 shouldMigrate only special-cased versionless
legacy booleans — versionless files with invalid gitCoAuthor values
(`"off"`, `[]`, etc.) skipped the migration and the loader stamped
`$version: 4` over the bad value. Runtime normalization then
silently re-enabled attribution. Extend shouldMigrate to fire on ANY
versionless non-object value at general.gitCoAuthor; the existing
migrate() body's drop-and-warn path resets it. Already-object
shapes (hand-edited to v4) still skip cleanly. Tests added.

0oAt (Copilot): `.terraform.lock.hcl` got dropped from generated-file
exclusion when `.lock` was removed from the blanket extension list
in 3c0e3293b. It's a generated provider lockfile in the same class
as `package-lock.json` and dominates Terraform-repo commits. Re-add
to EXCLUDED_FILENAMES and add a regression test covering both
repo-root and module-nested locations.

* fix(attribution): harden restoreFromSnapshot against corrupt payloads

1KMY (Copilot): snapshot.surface was copied without type validation.
A corrupted/partially-written snapshot with a non-string surface
(e.g. {}, 42, null) would later be serialized into the git note as
"[object Object]" and used as a Map key downstream, breaking the
expected payload shape. Type-check and fall back to the current
client surface for any non-string (or empty-string) value.

1KLq (Copilot): per-field sanitiseCount enforced
`promptCount >= 0` and `promptCountAtLastCommit >= 0` independently,
but never the cross-field invariant. A snapshot with
promptCountAtLastCommit > promptCount would surface a negative
getPromptsSinceLastCommit() and propagate as a "(-N)-shotted"
trailer into PR text. Clamp atLastCommit to total on restore.

1KL_ (Copilot): when a snapshot carried both the symlinked and
canonical paths for the same file (a session straddling the
canonicalisation fix), `set(realpathOrSelf(k), ...)` overwrote the
first entry with the second, silently dropping the AI contribution
the first form had accumulated. Merge instead: sum aiContribution
and OR aiCreated when collapsing duplicate keys.

Tests cover all three branches: non-string surface fallback,
promptCount clamp, and duplicate-key merge.

* fix(attribution): roll back snapshot dedup key on sync appendRecord failure

1UMh (Copilot): appendRecord can throw synchronously before returning
a promise — e.g. when ensureConversationFile() rethrows a non-EEXIST
writeFileSync error. The async .catch() handler attached to the
promise never runs in that case, so the optimistic dedup-key set
sticks on a write that never landed and permanently suppresses
identical retries. Roll back lastAttributionSnapshotJson in the outer
catch too. Regression test forces writeFileSync to throw EACCES on
the first invocation, then asserts the second identical snapshot
attempt fires a fresh write rather than getting deduped.

* docs(attribution): align cleanup-branch comments with noteCommitWithoutClearing

Three doc/test-fixture stale-after-refactor cleanups (Copilot
4MDx / 4MEI / 4MEa):

- shell.ts:1944 (around the stagedInfo === null branch): the comment
  still claimed the finally block "falls back to a full clear", but
  1ece87438 switched analysis-failure cleanup to
  noteCommitWithoutClearing(). Update the comment so the reasoning
  matches what the code actually does (and so a future reader doesn't
  reintroduce the wholesale clear thinking it's already there).

- shell.ts: getCommittedFileInfo docstring carried the same stale
  "full clear" claim for the `null` return value. Update to describe
  the noteCommitWithoutClearing() fallback and the smaller-evil
  trade-off for the just-committed file.

- chatRecordingService.test.ts: baseSnapshot fixture for the
  recordAttributionSnapshot tests still carried `baselines: {}`,
  even though that field was removed from AttributionSnapshot in
  296fb55ae's dead-code purge. Structural typing let it compile,
  but the fixture didn't reflect the production shape — drop it.

* fix(attribution): restore fire-and-forget appendRecord, route rollback via callback

6OcJ (Copilot): refactor in 715c258fb returned a Promise from
appendRecord so the snapshot dedup-key path could chain rollback —
but recordUserMessage / recordAssistantTurn / recordAtCommand /
recordSlashCommand / rewindRecording all call appendRecord without
await or .catch(). A transient jsonl.writeLine rejection on any of
those would surface as an unhandled-promise-rejection (warning, or
crash on --unhandled-rejections=throw).

Restore the original fire-and-forget semantics: appendRecord again
returns void and internally swallows async failures (logging via
debugLogger). Per-record failure reactions are routed through an
optional onError callback — recordAttributionSnapshot uses this to
roll back lastAttributionSnapshotJson when the write that set it
ends up rejecting.

Tests: add a fire-and-forget regression that mocks writeLine to
reject and asserts no unhandledRejection events fire while the
existing snapshot rollback tests (sync + async) still pass via the
new callback path.

* fix(attribution): GIT_DIR repo-shift bail, snapshot envelope validation, narrow legacyTypes

80ME (gpt-5.5 /review, [Critical]): tokeniseSegment unconditionally
stripped every leading KEY=value token. `GIT_DIR=elsewhere/.git git
commit ...` was therefore treated as an in-cwd commit, picked up the
Co-authored-by trailer, and produced a per-file note that landed
against our cwd's HEAD even though the actual commit went to a
different repo. Define a GIT_ENV_SHIFTS_REPO set (GIT_DIR,
GIT_WORK_TREE, GIT_COMMON_DIR, GIT_INDEX_FILE, GIT_NAMESPACE) and
have tokeniseSegment refuse to parse any segment whose leading env
block (including the env-wrapper's KEY=VALUE block) carries one of
these. Identity / date variables (GIT_AUTHOR_*, GIT_COMMITTER_*) are
deliberately NOT in the set — they tweak metadata but don't relocate
the repo. Tests cover plain prefix, env-wrapped prefix, and a
GIT_COMMITTER_DATE positive control that should still get the trailer.

8EeQ (Copilot): restoreFromSnapshot received `snapshot as
AttributionSnapshot` from a structural cast off `unknown` (the
resume path), so its TS-typed shape was only a hint. A corrupted
JSONL line (non-object / array / wrong type discriminator / missing
type) would skip past the version check straight into
Object.entries(snapshot.fileStates) — and a non-object fileStates
(an array, say) seeded fileAttributions with numeric-string keys.
Add envelope-level shape gates (isPlainObject + type discriminator)
and a fileStates plain-object check before iterating; both bail to a
clean reset rather than poisoning the singleton. Tests added.

8Eej (Copilot): SettingDefinition.legacyTypes was typed as
SettingsType[] which includes 'enum' and 'object' — JSON Schema's
`type` keyword doesn't accept those values. Adding
`legacyTypes: ['enum']` would silently produce an invalid
settings.schema.json. Narrow the field's type to
ReadonlyArray<'boolean' | 'string' | 'number' | 'array'> (the
JSON-Schema-primitive subset). Future complex-shape legacy support
should land its own branch in convertSettingToJsonSchema.

* docs(attribution): correct legacyTypes / EXCLUDED_DIRECTORY_SEGMENTS comments

9Ta_ (Copilot): the JSDoc on legacyTypes claimed JSON Schema's
`type` keyword does not accept `'object'` — that's wrong; `'object'`
IS a valid JSON Schema type. Reword to reflect the actual rationale:
`'enum'` is not a valid JSON Schema `type` value at all (enum
constraints use the `enum` keyword), and a bare `{type: 'object'}`
would accept any object regardless of what the field's pre-expansion
shape actually allowed. The narrowed `boolean | string | number |
array` set is exactly what the one-liner generator can faithfully
emit; richer legacy shapes belong in their own branch of
convertSettingToJsonSchema.

9Tbs (Copilot): the comment in generatedFiles.ts referenced
`EXCLUDED_DIRECTORIES`, but the constant is `EXCLUDED_DIRECTORY_SEGMENTS`
(renamed during the segment-boundary refactor). Update the
reference so a future maintainer scanning for the rule doesn't
chase a non-existent identifier.

* fix(attribution): SHA-pin git notes, on-disk hash divergence detection, env -C cwd-shift

tanzhenxin review #1 — Note targets symbolic HEAD, not captured SHA:
buildGitNotesCommand hard-coded 'HEAD' as the target; postHead was
captured at commit-detection time but only used for the !== preHead
diff. Between that capture and the execFile, three more awaited git
calls run — anything that moves HEAD in the same cwd (post-commit
hook, chained `commit && tag -m`, parallel process) silently lands
the note on the wrong commit because of `-f`. Thread postHead
through buildGitNotesCommand as a required `targetCommit` arg.
Test asserts the targeted SHA, not the symbolic ref.

tanzhenxin review #2 — Accumulator has no baseline:
recordEdit was monotonic per-path with no reset for out-of-band
mutations. Re-instate FileAttribution.contentHash and:
- recordEdit hashes the input `oldContent` and resets the per-file
  accumulator if it doesn't match what AI's last write recorded
  (catches paste-replace via external editor, manual save, etc.
  WHEN AI subsequently edits the same file again).
- New validateOnDiskHashes() rehashes every tracked file's CURRENT
  on-disk content and drops entries whose hash diverged. Called
  from attachCommitAttribution before matchCommittedFiles so a
  commit can never credit AI for a human-only diff. Deleted files
  (readFileSync throws) are left alone — the commit's deletion
  record is what the note should reflect.

tanzhenxin review #4 — Failed-commit / staleness leak:
The recordEdit divergence check above + commit-time
validateOnDiskHashes together catch tanzhenxin's exact scenario
(AI edits a.ts → hook rejects → user manually edits a.ts → user
commits → no AI credit because validateOnDiskHashes drops the
stale entry). The !commitCreated branch still preserves
attributions to keep the submodule case working — the staleness
problem is now solved at the next commit's validation step.

Self-review item — env -C / --chdir treated as repo-shifting:
Added ENV_FLAGS_SHIFT_CWD set covering -C / --chdir. tokeniseSegment
returns null for `env -C DIR git commit ...` segments — same
contract as a leading GIT_DIR=... assignment. Without this we'd
either misidentify /elsewhere as the program (silently dropping
attribution) or, worse if -C went into the value-skip set,
trailer-inject onto a commit that lands in /elsewhere's repo. Tests
added alongside the existing GIT_DIR repo-shift cases.

339 tests pass; typecheck clean.

* fix(attribution): pickBool intent-aware, shouldClear gate, ETIMEDOUT surface, drop dead exports

-wgA + -wg0 (deepseek): pickBool defaulted non-boolean to true,
turning a hand-edited `{ commit: "false" }` into enabled
attribution. Replace with intent-aware parsing: "true"/"yes"/"on"/
"1" → true, "false"/"no"/"off"/"0"/"" → false, anything else
(unknown strings, non-1 numbers, objects, arrays, null) → false.
Genuinely-absent sub-fields still default to true (schema default).
Migration test scenarios covered. Tests now cover ~17 input cases
across both string/number/null/object/unknown forms.

-wgq (deepseek): when buildGitNotesCommand returned null (oversized
payload) or git notes itself failed, the finally block called
clearAttributedFiles(committedAbsolutePaths) — irreversibly
deleting per-file attribution data the user might need to amend &
retry. Introduce a separate `shouldClear` set that's only assigned
on successful note write OR explicit toggle-off. Failure paths
(oversized, exitCode != 0, exception, analysis failure) leave
shouldClear null so the finally block calls noteCommitWithoutClearing
instead — preserving per-file state for the user's recovery.

9p7W (Copilot): execFile callback coerced ETIMEDOUT / SIGTERM
(timeout) into a generic exitCode=1 warning. Detect both
`error.code === 'ETIMEDOUT'` and `error.killed === true &&
error.signal === 'SIGTERM'` so the user-visible warning correctly
names "timed out after 5s" instead of "exited 1".

-wg7 (deepseek): formatAttributionSummary and getAttributionNotesRef
were exported but had zero production callers (only tests). Remove
the dead exports + their tests (~40 LOC). If/when a logging surface
needs them, they can be re-introduced.

-wgb (deepseek): tokeniseSegment doesn't recursively unwrap
`bash -c '...'` / `sh -c` / `zsh -c`, so addCoAuthorToGitCommit
won't splice the trailer into a wrapped command. The background
refusal AND the post-commit note path DO catch the wrapped commit
because stripShellWrapper at the top of execute peels the wrapper
before gitCommitContext / getGitHead run — so the worst-case
("background bash -c 'git commit' bypasses the guard") doesn't
materialize. The remaining gap (no Co-authored-by trailer for
bash -c-wrapped commits) requires recursively splicing into the
inner script with proper bash single-quote re-quoting; significant
enough that it's worth its own PR. Documented as a partial-coverage
limitation.

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