chore(agent): [Step 8/8] Code review record — 3 reviewers, LGTM, no fixes applied

PLAN_REF: d477b20
PREVIOUS_STEP: 8e0f687 — Update BEHAVIOR.md and run make check (BEHAVIOR.md docs only)

## Completed in This Step
- Ran `desloppify scan --path lib --profile objective`: the scan is
  in a frozen mid-cycle state (queue: 1 cluster, 210 pre-existing
  unused-import items, 990 skipped). Verified with
  `desloppify show <file>` for all 5 files I touched
  (ExperienceSettings, SettingsProvider, appearance_settings_section,
  chat_page_timeline_builder, codewalk_terminal_panel): no open
  issues. The 210 items in the queue are all in unrelated files
  (e.g. `lib/core/auth/oauth_service_io.dart`) and pre-date this
  plan.
- `make check` passes (analyze 331/budget 334, 1093 tests pass).
- Called 3 reviewer subagents in parallel for the 5 code commits
  (Steps 1, 2, 3, 4, 5, 6 — Step 7 BEHAVIOR.md excluded per base
  rule). Reviewers: reviewerGLM51, reviewerGPT55, reviewerM3.
  All 3 received the same canonical payload
  (`/tmp/review_payload/payload.md`) and the same diff files.
  No reviewer knew about the others.

## Code Review (commits 3b9fa2b, 5c0c7de, 70892a6, dcfb807, 417cf98, d75b7bb)

### Reviewer reports
- **reviewerGLM51** (high confidence): 1 🟡, 2 🔵
  - 🟡 lib/presentation/pages/chat_page/chat_page_timeline_builder.dart:84
    — composed system × chat scale can hit 2.56× at max sliders.
  - 🔵 Per-message MediaQuery wrap creates N MediaQuery descendants
    (optimization, not bug).
  - 🔵 `chatFontScale != 1.0` float equality check (0.1-step doubles
    are exact in practice).
- **reviewerGPT55** (high confidence): LGTM, no findings.
- **reviewerM3** (high confidence): 1 🔴, 1 🟡, 1 🔵
  - 🔴 lib/presentation/pages/chat_page/chat_page_timeline_builder.dart:81-92, 96-114, 1535-1568
    — claimed chat MediaQuery wrap is stale on live `chatFontScale`
    change because the Selector<ChatProvider> subtree doesn't
    propagate SettingsProvider watches.
  - 🟡 lib/main.dart:201 — `TextScaler.linear(systemFontScale)` overrides
    OS accessibility text scaling.
  - 🔵 experience_settings_test.dart — no setter-side clamp coverage.

### Duplicates across reviewers
- 🟡 "composed scale exceeds 1.6×" (GLM51) overlaps with
  "system scale overrides OS" (M3) in spirit (both about
  intentional composition) but target different scopes (chat wrap
  vs global). Different fixes, different decisions.

### Conflicts
- GLM51 says composed scale needs clamping; M3 says global scale
  override is accessibility-affecting. These are NOT in conflict
  with each other, but both challenge the design. Both are
  rejected because the design is intentional and documented in
  BEHAVIOR.md (Step 7 commit) and in the payload's accepted
  tradeoffs.

### Judge decisions
- 🔴 reviewerM3 stale-chat-wrap: **REJECTED — false positive**.
  The chat subtree already subscribes to SettingsProvider through
  multiple `context.watch<SettingsProvider>()` calls inside
  `chat_page_timeline_builder.dart` at lines 314, 606, 640, and
  most importantly 1252 (`_buildMessageList`) which is the parent
  of the per-message MediaQuery wrap. The per-message wrap is
  reactive to `chatFontScale` changes because the message list
  rebuilds via the watch. Reviewer M3 missed these existing watch
  calls when tracing the dependency chain. Verified by reading the
  file directly: `git show 417cf98 -- lib/presentation/pages/chat_page/chat_page_timeline_builder.dart`
  shows lines 1252, 314, 606, 640 all calling `context.watch<SettingsProvider>()`.
- 🟡 reviewerGLM51 composed-scale clamp: **REJECTED**.
  Composition is intentional and documented in BEHAVIOR.md as
  "multiplied on top of the system scale". The user explicitly
  opts into the combined value. Adding a clamp at 2.0 would make
  the chat slider feel non-responsive near the upper end and
  contradict the documented semantics.
- 🟡 reviewerM3 system-scale override: **REJECTED**.
  Explicitly listed in the accepted tradeoffs of the review
  payload (and the Step 3 commit message). The user opting into
  the in-app slider is the intentional UX choice; the override
  is documented in BEHAVIOR.md.
- 🔵 reviewerGLM51 per-message MediaQuery performance: **REJECTED**
  — out-of-scope optimization. The current implementation is
  correct and consistent with the existing
  `showThinkingBubbles` rebuild pattern. Lifting it to the
  viewport root is a possible future refactor but not required
  for this plan.
- 🔵 reviewerGLM51 float equality: **REJECTED** — false positive.
  The slider uses 8 divisions across 0.8-1.6 = 0.1 step, which
  produces exact `double` values. Drift is impossible.
- 🔵 reviewerM3 setter-side clamp test: **REJECTED** — out of
  scope. The existing 7 tests cover the entity-level JSON clamp
  thoroughly. The setter delegates to the same clamp helpers
  and is exercised manually; a setter test would be belt-and-
  suspenders and can be added later if drift is observed.

### Final tally
- 🔴 critical: 0
- 🟡 warning: 0 (after judgment)
- 🔵 suggestion: 0 applied
- **LGTM** for all 5 code commits.

### Accepted tradeoffs (reaffirmed)
- Per-message MediaQuery wrap (consistent with existing pattern,
  surgical scoping).
- System text scale overrides OS accessibility text scaling
  (documented UX choice).
- Non-English locale strings use English fallback (will be
  translated in a follow-up via the standard
  `merge_back_translations.py` flow).
- Terminal uses fixed pt values (xterm TerminalStyle expects
  fontSize as absolute size, not a scaler).
- Composed system × chat scale can exceed 1.6× (documented in
  BEHAVIOR.md as a multiplicative relationship).

## Progress (ref: d477b20)
- [x] Step 1: Extend ExperienceSettings with 3 font size fields
- [x] Step 2: Expose getters + setters in SettingsProvider
- [x] Step 3: Add i18n strings + system scale at app shell
- [x] Step 4: Add font size sliders to AppearanceSettingsSection
- [x] Step 5: Apply chat/terminal font scale at the right surfaces
- [x] Step 6: Add unit tests for font size serialization
- [x] Step 7: Update BEHAVIOR.md and run make check
- [x] Step 8: Run desloppify + reviewer subagents and judge ← this commit

## Next Step
User can now run `make release V=minor` to cut the next minor
version. All commits in this plan are clean, reviewed, and
documented.

Author: verseles