…, fix pricing display, simplify model matching, fix changelog links, add PartialEq for Tool (#3)

Sub-area #3 of the v0.6.6 UI redesign (issue #121).

Introduces `crates/tui/src/tui/widgets/tool_card.rs` — a small,
self-contained vocabulary module that owns:

- `ToolFamily` enum (Read / Patch / Run / Find / Delegate / Fanout /
  Think / Generic) and the verb-glyph + label per family
  (▷ read, ◆ patch, ▶ run, ⌕ find, ◐ delegate, ⋮⋮ fanout, … think)
- `tool_family_for_title` — maps the legacy header titles
  (`"Shell"`, `"Patch"`, `"Workspace"`, `"Search"`, `"Diff"`, `"Image"`)
  to a family, so existing call sites pick up the new glyph without
  re-architecture
- `tool_family_for_name` — maps actual tool names
  (`agent_spawn`, `apply_patch`, etc.) for `GenericToolCell`, which
  shares the catch-all `"Tool"` title across every model-facing tool
- `CardRail` + `rail_glyph` — the `╭ │ ╰` rail vocabulary, declared
  here so any future per-card refactor has the matching glyphs

Wires the verb glyph + label into `render_tool_header` and adds a
`render_tool_header_with_family` overload so `GenericToolCell` can
route by tool name rather than the generic title. The header now reads
`<spinner> <verb-glyph> <verb> <state>` instead of
`<spinner> <Title-Case-Word> <state>`.

Existing parity tests for ExecCell / PlanUpdate are updated to assert
against the new header structure (verb + glyph) — the colour wiring is
unchanged. New tests pin the verb-glyph format end-to-end:
`agent_spawn` → `◐ delegate`, exec → `▶ run`.

Spinner cadence (TOOL_STATUS_SYMBOL_MS = 720 ms) is unchanged — the
spec already matched.

Deferred to a follow-up: full per-card rail (`╭ │ ╰`) refactor that
threads `CardRail` through every cell render path. The vocabulary is
in place; the layout pass is the next bite.

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

Sub-area Hmbown#3 of the v0.6.6 UI redesign (issue Hmbown#121).

Introduces `crates/tui/src/tui/widgets/tool_card.rs` — a small,
self-contained vocabulary module that owns:

- `ToolFamily` enum (Read / Patch / Run / Find / Delegate / Fanout /
  Think / Generic) and the verb-glyph + label per family
  (▷ read, ◆ patch, ▶ run, ⌕ find, ◐ delegate, ⋮⋮ fanout, … think)
- `tool_family_for_title` — maps the legacy header titles
  (`"Shell"`, `"Patch"`, `"Workspace"`, `"Search"`, `"Diff"`, `"Image"`)
  to a family, so existing call sites pick up the new glyph without
  re-architecture
- `tool_family_for_name` — maps actual tool names
  (`agent_spawn`, `apply_patch`, etc.) for `GenericToolCell`, which
  shares the catch-all `"Tool"` title across every model-facing tool
- `CardRail` + `rail_glyph` — the `╭ │ ╰` rail vocabulary, declared
  here so any future per-card refactor has the matching glyphs

Wires the verb glyph + label into `render_tool_header` and adds a
`render_tool_header_with_family` overload so `GenericToolCell` can
route by tool name rather than the generic title. The header now reads
`<spinner> <verb-glyph> <verb> <state>` instead of
`<spinner> <Title-Case-Word> <state>`.

Existing parity tests for ExecCell / PlanUpdate are updated to assert
against the new header structure (verb + glyph) — the colour wiring is
unchanged. New tests pin the verb-glyph format end-to-end:
`agent_spawn` → `◐ delegate`, exec → `▶ run`.

Spinner cadence (TOOL_STATUS_SYMBOL_MS = 720 ms) is unchanged — the
spec already matched.

Deferred to a follow-up: full per-card rail (`╭ │ ╰`) refactor that
threads `CardRail` through every cell render path. The vocabulary is
in place; the layout pass is the next bite.

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

🔴 Fix Hmbown#1 (Embedder blocks async runtime):
- Pre-warm embedder in init_vector_db() via warmup_embedder()
- Model downloaded during startup, not first retrieval
- Eliminates 5-10s UI freeze on first embed call

🔴 Fix Hmbown#2 (Compaction summary pollution):
- store_compaction_summary_to_vector_db() now extracts only
  the summary section from the SystemPrompt, stripping
  boilerplate headers and workflow context
- Uses regex extraction between ## Summary and ## Workflow markers

🔴 Fix Hmbown#3 (No vector index → full table scan):
- New ensure_vector_index() in LanceDbBackend
- Checks list_indices() for existing IVF-PQ index on embedding column
- Creates missing index via table.create_index(["embedding"], Index::Auto)
- Called from ensure_tables() for all three tables

🔴 Fix Hmbown#4 (Compaction threshold regression for non-vector users):
- Added MINIMUM_AUTO_COMPACTION_TOKENS_WITHOUT_VECTOR = 500K
- should_compact() now accepts vector_db_enabled: bool
- Non-vector users keep 500K floor; vector users use 50K floor
- auto_floor_tokens=0 (explicit disable by tests) bypasses both floors
- token_threshold default restored to 800K (fallback only;
  real values come from compaction_threshold_for_model_and_effort)

🟡 Fix Hmbown#7 (No score threshold → noise injection):
- search_memories() and search_summaries() now filter
  results where score < 0.4 before returning
- Prevents low-quality retrieval from polluting system prompt

Tests: 62/62 compaction ✓, 17/17 vector_db ✓

🔴 Hmbown#1 Embedder blocks async runtime:
  - Pre-warm embedder in init_vector_db() via warmup_embedder()
  - Model downloaded at startup, eliminating 5-10s UI freeze

🔴 Hmbown#2 Compaction summary boilerplate pollution:
  - store_compaction_summary_to_vector_db() now extracts only
    the actual summary section using regex, stripping headers
    and workflow context from embeddings

🔴 Hmbown#3 No vector index → full table scan:
  - New ensure_vector_index() checks list_indices() for IVF-PQ
  - Creates missing index via create_index(["embedding"], Auto)
  - Called from ensure_tables() for all 3 tables

🔴 Hmbown#4 Compaction threshold regression:
  - Added MINIMUM_AUTO_COMPACTION_TOKENS_WITHOUT_VECTOR = 500K
  - should_compact() accepts vector_db_enabled: bool
  - Non-vector users keep 500K floor; vector users get 50K
  - auto_floor_tokens=0 bypasses both (test compatibility)
  - token_threshold default restored to 800K

🟡 Hmbown#7 Score threshold filtering added:
  - search_memories() and search_summaries() filter score < 0.4

Tests: 62/62 compaction ✓, 17/17 vector_db ✓, 99/100 engine ✓

…trol, verify fast-path, naming

- combined_hash now hashes full tool JSON (name + description + schema),
  not just tool names, so schema/description changes are detected (Hmbown#1).
- build_messages preserves cache_control from SystemPrompt::Blocks so
  DeepSeek context-cache breakpoints are not lost (Hmbown#2).
- FrozenPrefix::verify() compares raw text before hashing to avoid
  redundant SHA-256 computation (Hmbown#3).
- build_messages uses self.message_count() for vector capacity (Hmbown#4).
- Strict-mode error message no longer references nonexistent
  /prefix-unfreeze command — suggests restart or config toggle (Hmbown#5).