Record the batched-VAD measurements and check heartbeat, bursts and cancel against the real sidecar

Co-Authored-By: Claude Opus 5.5 <[email protected]>

tests/server-engine.md

@@ -31,6 +31,9 @@ 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.
+With `FW_INTEGRATION=1` it also pushes the whole 15-min `en_alien` clip
+(`tiny.en`) through `POST /api/transcribe` — heartbeat lines before the first
+burst, segments in bursts — and cancels a batched run after its first burst.
 
 - [ ] The `real faster-whisper sidecar` describe block passes.
 
@@ -52,7 +55,8 @@ check the mode routing, the one-model cache and cancel between segments.
       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.
+      arrives as a single segment at the end. Each segment covers one VAD
+      speech chunk (up to 30 s), not one sentence — expected (D-WS5a).
 - [ ] 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