refactor(recording): drop RecordingSession.mic_activity (retired) (FR-SPK)

src-tauri/src/lib.rs

@@ -85,13 +85,6 @@ pub struct RecordingSession {
     /// auto-labeled "You" instead of a clustered "S1"/"S2". `None` when the
     /// mic is disabled (same conditions as `mic_capture`).
     pub mic_voice_sample: Option<Arc<audio::VoiceSample>>,
-    /// Phase 3 (FR-SPK): per-100ms timeline of when the mic (the user, "You")
-    /// was speaking, in `audio.wav` frame time. `stop_recording` turns it into
-    /// "You" spans and diarizes the far side with those ranges masked out, so
-    /// the mic is never clustered. `None` when the mic is disabled (same
-    /// conditions as `mic_capture`); then attribution falls back to the
-    /// voiceprint pass.
-    pub mic_activity: Option<Arc<audio::MicActivity>>,
     /// `audio.wav` channel layout for this recording (FR-SPK): `"split"` (mic
     /// enabled → stereo mic-left/loopback-right) or `"summed"` (mic off). Passed
     /// to `finalize_meeting` so playback/diarization/export can branch on it.