WIP: uncommitted work at pause (session limit)

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

tests/server-engine.md

@@ -21,7 +21,16 @@ FW_INTEGRATION=1 bun test tests/transcribe.test.ts
 ```
 
 Runs the real sidecar end to end (spawn → ready handshake → `tiny.en` load →
-transcribe → done). First run downloads ~75 MB of weights from the Hub.
+transcribe → done), then the first 60 s of `tests/audio_files/en_alien.opus`
+(needs `ffmpeg`) in both decoding modes (D-WS5a): `file` (faster-whisper's
+`BatchedInferencePipeline` + Silero VAD, what `POST /api/transcribe` uses) and
+`live` (sequential, what server-live passes use). First run downloads ~75 MB
+of weights from the Hub. Point `SIDECAR_PYTHON` at a virtualenv's python if
+faster-whisper isn't installed for `python3` itself.
+
+Without faster-whisper at all, `bun test tests/transcribe.test.ts` still runs
+the real `server-py/sidecar.py` against a stub (`tests/fixtures/stub_fw`) to
+check the mode routing, the one-model cache and cancel between segments.
 
 - [ ] The `real faster-whisper sidecar` describe block passes.
 
@@ -39,7 +48,13 @@ transcribe → done). First run downloads ~75 MB of weights from the Hub.
    where `audio.f32` is raw float32 mono 16 kHz PCM).
 5. Transcribe the same clip through the server engine.
 
-- [ ] Segments stream in as JSON lines (not one blob at the end).
+- [ ] Segments stream in as JSON lines (not one blob at the end). With the
+      batched pipeline (D-WS5a) they arrive in bursts — one burst per 8
+      speech chunks (≈ up to 4 min of audio) — with blank heartbeat lines
+      every 5 s in between; on a clip under ~30 s of speech, everything
+      arrives as a single segment at the end.
+- [ ] Cancelling a long server transcription (abort / page refresh) stops
+      the sidecar within one burst; the next request then starts normally.
 - [ ] Both transcripts agree in content (minor punctuation/casing drift
       between Transformers.js and faster-whisper is expected).
 - [ ] Signed out, the toggle is gone and `POST /api/transcribe` answers 401.