Fills events_ai.py against the frozen M7 contract:
- detect_candidates: RMS x spectral-flux, local-max over a 10s neighborhood,
>=P90, with an AC-RMS (std) silence/DC floor so flat audio yields no events.
Matches the fixture ground-truth pulses [3,10,17] within ~0.02s (<0.5s).
- GeminiClassifier (native video), ClaudeClassifier (claude-opus-4-8,
messages.parse, adaptive thinking, no temperature), LocalClassifier
(OpenAI-compatible, 6 frames, 1 retry). SDKs imported lazily.
- get_classifier: FESTIVAL4D_CLASSIFIER selection; unconfigured -> None
(candidates-only, logged).
- prepare_inputs: ffmpeg 3s clip (<=720p, audio kept) + 6 JPEGs (<=768px).
- run_events: reference-audio detect -> classify (insert-once in final state,
since db.py has no update-event helper); per-candidate exception isolation;
whole-track replaces machine events (keeps user edits), windowed is additive.
test_events_ai.py: candidate-vs-ground-truth (no ffmpeg/API), stub-classifier
orchestration, exception isolation, degradation, provider selection, silence.
Also updates the now-obsolete api stub test (test_detect_events_endpoint) to the
real M3 {result, events} shape; frozen api.py unchanged (see CR-1). pytest: 90 passed.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
