fix(quality-badge): distinguish lossy formats from CD quality

MP3 and other lossy formats (aac, m4a, ogg, opus, wma) at CD-like
sample rates (44.1-48kHz) were incorrectly shown as "CD" quality
because bitDepth check came before format check.

Changes:
- Add format prop to QualityBadge, NowPlayingBar, ExpandedPlayer
- Add format field to PlayingTrack interface
- Check for lossy formats BEFORE checking bitDepth/samplingRate
- New 'mp3-cd' tier for lossy formats at CD sample rates
- Uses /mp3-cd.svg icon for this tier

src/routes/+page.svelte

@@ -1638,6 +1638,7 @@
       quality,
       bitDepth: track.bit_depth,
       samplingRate: track.sample_rate ? track.sample_rate / 1000 : undefined,  // Convert Hz to kHz (44100 → 44.1) - NO ROUNDING
+      format: track.format,
       isLocal: true
     }, { isLocal: true });
   }
@@ -2695,6 +2696,7 @@
         quality={currentTrack.quality}
         bitDepth={currentTrack.bitDepth}
         samplingRate={currentTrack.samplingRate}
+        format={currentTrack.format}
         {isPlaying}
         onTogglePlay={togglePlay}
         onSkipBack={handleSkipBack}
@@ -2779,6 +2781,7 @@
         qualityLevel={currentTrack.quality.includes('24') ? 5 : 3}
         bitDepth={currentTrack.bitDepth}
         samplingRate={currentTrack.samplingRate}
+        format={currentTrack.format}
         {isPlaying}
         onTogglePlay={togglePlay}
         onSkipBack={handleSkipBack}