fix(media): catch autoplay rejections from play()

Notification sounds called `audio.play()` without handling the promise,
so every message that arrived before the user interacted with the page
(e.g. right after launch) logged an uncaught NotAllowedError — 15 in a
short test run. Same pattern in the video thumbnail loader, the voice
preview (which now also resets its Play button) and useMediaPlay.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA

src/app/utils/dom.ts

@@ -134,7 +134,9 @@ export const loadVideoElement = (url: string): Promise<HTMLVideoElement> =>
 
     video.src = url;
     video.load();
-    video.play();
+    // Only nudges the decoder toward the first frame; `onloadeddata` settles
+    // the promise, so an autoplay refusal here is harmless.
+    video.play().catch(() => undefined);
   });
 
 export const getThumbnailDimensions = (width: number, height: number): [number, number] => {