feat(ui): wire LevelMeter and device notice into the header (T7.3)

src/App.svelte

@@ -6,6 +6,7 @@
   import SummaryPanel from "./lib/views/SummaryPanel.svelte";
   import Settings from "./lib/views/Settings.svelte";
   import ConsentNotice from "./lib/components/ConsentNotice.svelte";
+  import LevelMeter from "./lib/components/LevelMeter.svelte";
   import { recording } from "./lib/stores/recording.svelte";
   import { settings } from "./lib/stores/settings.svelte";
   import { meetings } from "./lib/stores/meetings.svelte";
@@ -70,6 +71,7 @@
     {:else}
       <button onclick={() => recording.stop()}>■ Stop</button>
       <span class="rec">Recording…</span>
+      <LevelMeter rms={recording.levelRms} peak={recording.levelPeak} />
       {#if settings.hardware}
         <span class="backend" title="Active transcription backend">{settings.hardware.active}</span>
       {/if}
@@ -77,6 +79,11 @@
         <input type="checkbox" checked={recording.retention} onchange={onToggleRetention} />
         <span>{recording.retention ? "saving" : "not saved"}</span>
       </label>
+      {#if recording.deviceNotice}
+        <span class="device-notice" role="status" title={recording.deviceNotice}>
+          ⚠ reconnecting audio device…
+        </span>
+      {/if}
     {/if}
     <select
       class="theme-select"
@@ -186,6 +193,10 @@
     color: var(--muted);
     cursor: pointer;
   }
+  .device-notice {
+    color: var(--warning);
+    font-size: 0.8rem;
+  }
   .consent-overlay {
     position: fixed;
     inset: 0;