docs(data-model): audio.wav split layout + audio_layout column; drop mic_activity.json (FR-SPK)

docs/03-data-model.md

@@ -14,9 +14,8 @@ Default root: `%LOCALAPPDATA%\WhispAssist\` (user-configurable, FR-STORE-2).
 │   └── spk-eres2net.onnx
 └── meetings\
     └── <meeting_id>\           # one folder per meeting (uuid)
-        ├── audio.wav           # canonical recording — present ONLY if "Record" was on (ADR-0009)
-        ├── voiceprint.wav      # mic-only 16kHz sample for "You" re-matching on reprocess (FR-SPK); lives/dies with audio.wav
-        ├── mic_activity.json   # Phase 3 "You" spans (mic-speech timeline) for per-stream attribution on reprocess (FR-SPK); local-only, lives/dies with audio.wav
+        ├── audio.wav           # canonical recording — present ONLY if "Record" was on (ADR-0009). Mic on → stereo split (L=mic/"You", R=loopback/"Speaker", `audio_layout=split`); mic off → summed. Playback folds to mono; export folds to dual-mono (ADR-0005 Phase 3.5)
+        ├── voiceprint.wav      # mic-only 16kHz sample for "You" re-matching on reprocess of a SUMMED recording (FR-SPK); lives/dies with audio.wav
         ├── transcript.json     # canonical transcript (segments+speakers+timings)
         ├── manual_notes.json   # raw user-authored notes captured live during recording
         ├── notes.md            # the final notes document: manual notes + transcript, merged at finalize
@@ -88,6 +87,7 @@ CREATE TABLE meetings (
     language        TEXT,                         -- detected/selected language code
     backend_used    TEXT,                         -- npu|nvidia|amd|intel|cpu
     model_used      TEXT,                         -- e.g. whisper-base
+    audio_layout    TEXT,                         -- split|summed|NULL; how audio.wav's channels are laid out (0009, ADR-0005 Phase 3.5)
     calendar_event_id TEXT,                       -- FK -> calendar_events.id (nullable)
     template_id     TEXT,                         -- note-template id (T8.1, FR-NOTE-5); catalog is
                                                     -- a built-in Rust list (notes::templates), not a table