Tick completed workstream 4 plan steps

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/plans/001-4-translate.md

@@ -64,21 +64,21 @@ Test `tests/models.test.ts`, new `tests/transcriptionOptions.test.tsx`.
 `taskForModel(modelId: string, task: WhisperTask): WhisperTask`;
 `TranscriptionOptions` prop `canTranslate: boolean`.
 
-- [ ] Failing tests: `canTranslate` false for turbo and every `.en`, true for the other multilingual
+- [x] Failing tests: `canTranslate` false for turbo and every `.en`, true for the other multilingual
   ids; `taskForModel("onnx-community/whisper-large-v3-turbo", "translate") === "transcribe"`,
   unchanged for `whisper-small`; unknown id → `"transcribe"`. `renderToStaticMarkup` of
   `TranscriptionOptions` with `canTranslate={false}` contains no "Translate to English" and no Task
   select; with `true` contains it.
-- [ ] Implement; App: `setTask(t => taskForModel(next, t))` in `handleModelSelect` and the server
+- [x] Implement; App: `setTask(t => taskForModel(next, t))` in `handleModelSelect` and the server
   auto-switch effect; runs pass `task: taskForModel(modelId, task)`.
-- [ ] Typecheck, fast suite; D-WS4a entry; commit.
+- [x] Typecheck, fast suite; D-WS4a entry; commit.
 
 ### Task 2: error stage for translation
 
 **Files:** `src/lib/errors.ts`, `tests/errors.test.ts`.
-- [ ] Failing test: `classifyError("Out of memory", { stage: "translate" })` → suggestion mentions a
+- [x] Failing test: `classifyError("Out of memory", { stage: "translate" })` → suggestion mentions a
   shorter transcript / closing tabs, not "smaller model"; network on `stage: "translate"` retryable.
-- [ ] Add `"translate"` to `ErrorStage`; commit with Task 3.
+- [x] Add `"translate"` to `ErrorStage`; commit with Task 3.
 
 ### Task 3: pure translation planning (`src/lib/translation.ts`)
 
@@ -94,7 +94,7 @@ Test `tests/models.test.ts`, new `tests/transcriptionOptions.test.tsx`.
 - `assembleTranslation(units, translated: string[]): { text; chunks }`.
 - Tests (`tests/translation.test.ts`): unit merging & timestamps, null end, no-chunk fallback, sentence
   splitting, Review Focus 1–3, assemble length mismatch throws, `guessSourceLanguage`.
-- [ ] Red → green → commit.
+- [x] Red → green → commit.
 
 ### Task 4: translate worker + protocol + measurement
 
@@ -111,8 +111,8 @@ unreachable and the model is not cached; run under the lock), `scripts/bench-tra
   `splitForTranslation` with the real tokenizer count; batches of `BATCH_SIZE` (measured).
 - Bundle + serve: `src/index.ts` dev route `/translate.worker.js`, `scripts/build.ts` emits and
   precaches it.
-- [ ] Measure en_alien.txt → da and da_festuge → en on onnxruntime-node (batch 1 vs 4 vs 8); record.
-- [ ] Commit.
+- [x] Measure en_alien.txt → da and da_festuge → en on onnxruntime-node (batch 1 vs 4 vs 8); record.
+- [x] Commit.
 
 ### Task 5: UI — `TranslatePanel`
 
@@ -129,9 +129,9 @@ unreachable and the model is not cached; run under the lock), `scripts/bench-tra
 - State resets whenever `result` changes; Cancel terminates the translate worker.
 - [ ] impeccable polish pass; screenshots light/dark × desktop/mobile; real headless-Chrome run of a
   translation (WASM) if feasible.
-- [ ] Commit.
+- [x] Commit.
 
 ### Task 6: docs + wrap-up
-- [ ] D-WS4b entry (models, licences, numbers); Architecture.md (translate worker), AGENTS.md rule
+- [x] D-WS4b entry (models, licences, numbers); Architecture.md (translate worker), AGENTS.md rule
   wording (two workers), WorkBreakdown, README if needed, `tests/offline.md` step.
 - [ ] typecheck, fast suite, build; `git rm` this plan; commit.