## Summary

- Adds `src/gui/MainWindow.cpp` and `src/gui/MainWindow.h` to the
`dorny/paths-filter` `build` group so the Windows CI job runs whenever
the hot file changes.
- The file is densely platform-guarded (`#ifdef Q_OS_WIN`, `Q_OS_MAC`,
`HAVE_PIPEWIRE`), so Linux-passing edits can still break MSVC.

## Motivation

Same class of failure has bitten us repeatedly:
- **#2633 → #2662** — unconditional `m_daxBridge` reference inside a
macOS-only guard, caught post-release.
- **#2670** — Windows behaviour change not exercised by CI.
- **v26.5.3 (#3024)** — `ClientPhaseRotator.cpp` bare `M_PI` broke MSVC
(needs `_USE_MATH_DEFINES`). Different file, same shape: path not on the
filter → `check-windows` didn't run → broken Windows build landed and
required a follow-up patch.

This PR closes the gap for the highest-leverage file. Other hot
platform-guarded files can be added later if their breakage rate
justifies the runner time.

## Cost

Most PRs continue to skip `check-windows` (the filter still excludes
most source paths). Cost increase is bounded to the subset of PRs that
touch MainWindow.cpp/.h, which is exactly the subset that needs the
coverage.

## Test plan

- [ ] CI: `check-paths` job runs and reports `build-changed=true` on
this PR (because `.github/workflows/**` is itself a watched path).
- [ ] CI: `check-windows` job runs and passes (no source changed, so it
should be a clean cache hit).
- [ ] After merge: next PR that touches `src/gui/MainWindow.cpp`
triggers `check-windows` automatically.

Closes #2671.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

## Summary

Drop the \`check-paths\` allow-list job that gated \`check-windows\` and
\`check-macos\` based on a hand-maintained set of files. Both
cross-platform CI builds now run on every PR.

## Why

The path-filter approach has been a chronic leaker. Every time a new
file gained a platform-guarded branch (\`#ifdef Q_OS_WIN\`, \`#ifdef
Q_OS_MAC\`, \`HAVE_PIPEWIRE\`, etc.) that wasn't on the allow-list, CI
silently skipped the relevant cross-platform check and the regression
surfaced at release tag time. The follow-up was always to add another
path to the filter — and then the same class of issue would resurface
elsewhere a few PRs later.

Pattern receipts:
- #796 — original \"MSVC issue slipped past CI\" lesson
- #2633 → #2662 — macOS \`m_daxBridge\` reference inside macOS-only
guard, missed
- #2670 — Windows behavior change not exercised by CI
- #2671 — added MainWindow.cpp/.h to filter after a miss
- #2929 → #3052 — WASAPI mono-mic recovery landed unverified; added
AudioEngine.cpp/.h
- #3210 — re-added AudioEngine after a relapse
- v26.5.3 — ClientPhaseRotator.cpp \`M_PI\` MSVC break slipped through
- #3241 (yesterday) — CwSidetonePortAudioSink WASAPI fix; entire
\`#ifdef Q_OS_WIN\` block never compiled by CI because the file wasn't
on the filter

## Trade-off

Cost: ~15-20 min of GitHub Actions runner time per PR (Windows + macOS
in parallel, both cached aggressively — cold ~5 min, warm ~2-3 min).

Benefit: a whole class of release-time regression we've been paying for
repeatedly.

## Test plan

- [x] YAML valid (\`python3 -c 'import yaml; yaml.safe_load(...)'\`)
- [ ] Confirm \`check-windows\` and \`check-macos\` actually run on this
PR (no longer marked \`skipping\`)
- [ ] Both pass

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

… (aethersdr#3028)

## Summary

- Adds `src/gui/MainWindow.cpp` and `src/gui/MainWindow.h` to the
`dorny/paths-filter` `build` group so the Windows CI job runs whenever
the hot file changes.
- The file is densely platform-guarded (`#ifdef Q_OS_WIN`, `Q_OS_MAC`,
`HAVE_PIPEWIRE`), so Linux-passing edits can still break MSVC.

## Motivation

Same class of failure has bitten us repeatedly:
- **aethersdr#2633 → aethersdr#2662** — unconditional `m_daxBridge` reference inside a
macOS-only guard, caught post-release.
- **aethersdr#2670** — Windows behaviour change not exercised by CI.
- **v26.5.3 (aethersdr#3024)** — `ClientPhaseRotator.cpp` bare `M_PI` broke MSVC
(needs `_USE_MATH_DEFINES`). Different file, same shape: path not on the
filter → `check-windows` didn't run → broken Windows build landed and
required a follow-up patch.

This PR closes the gap for the highest-leverage file. Other hot
platform-guarded files can be added later if their breakage rate
justifies the runner time.

## Cost

Most PRs continue to skip `check-windows` (the filter still excludes
most source paths). Cost increase is bounded to the subset of PRs that
touch MainWindow.cpp/.h, which is exactly the subset that needs the
coverage.

## Test plan

- [ ] CI: `check-paths` job runs and reports `build-changed=true` on
this PR (because `.github/workflows/**` is itself a watched path).
- [ ] CI: `check-windows` job runs and passes (no source changed, so it
should be a clean cache hit).
- [ ] After merge: next PR that touches `src/gui/MainWindow.cpp`
triggers `check-windows` automatically.

Closes aethersdr#2671.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

## Summary

Drop the \`check-paths\` allow-list job that gated \`check-windows\` and
\`check-macos\` based on a hand-maintained set of files. Both
cross-platform CI builds now run on every PR.

## Why

The path-filter approach has been a chronic leaker. Every time a new
file gained a platform-guarded branch (\`#ifdef Q_OS_WIN\`, \`#ifdef
Q_OS_MAC\`, \`HAVE_PIPEWIRE\`, etc.) that wasn't on the allow-list, CI
silently skipped the relevant cross-platform check and the regression
surfaced at release tag time. The follow-up was always to add another
path to the filter — and then the same class of issue would resurface
elsewhere a few PRs later.

Pattern receipts:
- aethersdr#796 — original \"MSVC issue slipped past CI\" lesson
- aethersdr#2633 → aethersdr#2662 — macOS \`m_daxBridge\` reference inside macOS-only
guard, missed
- aethersdr#2670 — Windows behavior change not exercised by CI
- aethersdr#2671 — added MainWindow.cpp/.h to filter after a miss
- aethersdr#2929 → aethersdr#3052 — WASAPI mono-mic recovery landed unverified; added
AudioEngine.cpp/.h
- aethersdr#3210 — re-added AudioEngine after a relapse
- v26.5.3 — ClientPhaseRotator.cpp \`M_PI\` MSVC break slipped through
- aethersdr#3241 (yesterday) — CwSidetonePortAudioSink WASAPI fix; entire
\`#ifdef Q_OS_WIN\` block never compiled by CI because the file wasn't
on the filter

## Trade-off

Cost: ~15-20 min of GitHub Actions runner time per PR (Windows + macOS
in parallel, both cached aggressively — cold ~5 min, warm ~2-3 min).

Benefit: a whole class of release-time regression we've been paying for
repeatedly.

## Test plan

- [x] YAML valid (\`python3 -c 'import yaml; yaml.safe_load(...)'\`)
- [ ] Confirm \`check-windows\` and \`check-macos\` actually run on this
PR (no longer marked \`skipping\`)
- [ ] Both pass

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>