fix: prevent music canplay callback from interrupting ABS playback start

When absPlayItem() paused S.audio, the stale canplay listener from the
last playCurrent() call still had a matching _playGen value and would
call S.audio.play() — triggering absInterrupt() which immediately paused
the ABS audio. Fix: export cancelMusicAutoplay() that bumps _playGen
before pausing, invalidating any pending canplay/guard callbacks.

Also shrink OK button and widen time input in sleep timer.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/abs.js

@@ -1,5 +1,6 @@
 import { S } from './state.js';
 import { esc, toast } from './utils.js';
+import { cancelMusicAutoplay } from './player.js';
 
 // ─── HTTP HELPERS ───
 // API calls are routed through the NovaSonic backend proxy to avoid CORS restrictions.
@@ -204,7 +205,7 @@ export async function absPlayItem(item) {
   const ap = S.absPlayer;
   const audio = _getAudio();
 
-  if (!S.audio.paused) S.audio.pause(); // stop music if playing
+  cancelMusicAutoplay(); // pause music + invalidate any stale canplay callbacks
   if (ap._sessionId) { absCloseSession(ap._sessionId); ap._sessionId = null; }
   _stopSync();
   audio.pause();