feat(ui): track live level + device notice in the recording store (T7.3)

src/lib/stores/recording.svelte.ts

@@ -10,12 +10,21 @@ class RecordingStore {
   segments = $state<TranscriptSegment[]>([]);
   /** Whether audio is being retained as .wav for the in-flight meeting (ADR-0009). */
   retention = $state(false);
+  /** Live input level for the waveform/meter (FR-CAP-5); 0 when not recording. */
+  levelRms = $state(0);
+  levelPeak = $state(0);
+  /** Set while a capture-device reconnect is in progress; cleared on recovery (FR-CAP-6). */
+  deviceNotice = $state<string | null>(null);
 
   async init() {
     await events.onRecordingState((p) => {
       const e = p as { state: "recording" | "paused" | "stopped"; elapsedMs: number };
       this.state = e.state === "stopped" ? "idle" : e.state;
       this.elapsedMs = e.elapsedMs ?? this.elapsedMs;
+      if (e.state === "stopped") {
+        this.levelRms = 0;
+        this.levelPeak = 0;
+      }
     });
     await events.onRetention((p) => {
       this.retention = p.record;
@@ -26,11 +35,19 @@ class RecordingStore {
       if (i >= 0) this.segments[i] = segment;
       else this.segments.push(segment);
     });
+    await events.onLevel(({ rms, peak }) => {
+      this.levelRms = rms;
+      this.levelPeak = peak;
+    });
+    await events.onDeviceChanged(({ recovered, message }) => {
+      this.deviceNotice = recovered ? null : message;
+    });
   }
 
   async start(title?: string, record = false) {
     this.segments = [];
     this.retention = record;
+    this.deviceNotice = null;
     this.meetingId = await api.startRecording(title, undefined, record);
     this.state = "recording";
   }
@@ -38,6 +55,9 @@ class RecordingStore {
   async stop() {
     if (this.meetingId) await api.stopRecording(this.meetingId);
     this.state = "idle";
+    this.levelRms = 0;
+    this.levelPeak = 0;
+    this.deviceNotice = null;
   }
 
   /** Toggle audio retention mid-meeting (FR-REC-1); caller must have gated consent already. */