Merge feat/297-cheaper-ai into feat/299-correlation-simplify

Resolve upload.py (no-scene fallback uses the new _correlate with #298's
non_event_chatter reason) and chatter_classifier docstring (gate built, off by
default). Fold intelligence._llm_bool into incident_correlator.parse_llm_bool (#88).

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

drb-c2-core/app/internal/recorrelation_sweep.py

@@ -65,7 +65,11 @@ def pipeline_worst_case_seconds(n_scenes: int = _BOUND_SCENES) -> float:
     _run_intelligence_pipeline."""
     openai_attempts = 1 + max(0, settings.openai_max_retries)
     stt_rounds = 2 if settings.stt_retry_on_degenerate else 1
-    stt = stt_rounds * openai_attempts * settings.stt_timeout_seconds
+    # A failed primary STT provider falls back to OpenAI (server-26#297), so
+    # the worst case is every configured target timing out in turn.
+    from app.internal.transcription import stt_targets
+    stt_providers = max(1, len(stt_targets()))
+    stt = stt_providers * stt_rounds * openai_attempts * settings.stt_timeout_seconds
     # Transcript correction (inside transcribe_call). gemini.generate_json only
     # re-issues a request when the model rejects a thinking level — a fast
     # 400, not a timeout — and google-genai itself does not retry.