refactor(quality-badge): simplify to only detect MP3 format

Simplified the lossy format detection since only MP3 is clearly lossy
among supported library formats (flac, m4a, wav, aiff, ape, mp3).
m4a can be either ALAC (lossless) or AAC (lossy) so it's not reliable.

- Removed LOSSY_FORMATS array, now only checks for 'mp3'
- Use /mp3.svg icon (text-only, more readable than mp3-cd.svg)
- Simplified tier to just 'mp3' instead of 'mp3-cd' and 'lossy'

src/lib/components/QualityBadge.svelte

@@ -13,21 +13,13 @@
     format
   }: Props = $props();
 
-  // Define lossy formats
-  const LOSSY_FORMATS = ['mp3', 'aac', 'm4a', 'ogg', 'opus', 'wma'];
-
   // Determine quality tier
   const tier = $derived.by(() => {
     const fmt = (format || quality || '').toLowerCase();
 
-    // Check for lossy formats FIRST - they should never be "CD" quality
-    const isLossyFormat = LOSSY_FORMATS.some(f => fmt.includes(f));
-    if (isLossyFormat) {
-      // MP3/lossy at CD-like sample rates gets special 'mp3-cd' tier
-      if (samplingRate && samplingRate >= 44.1 && samplingRate <= 48) {
-        return 'mp3-cd';
-      }
-      return 'lossy';
+    // Check for MP3 FIRST - it should never be "CD" quality
+    if (fmt.includes('mp3')) {
+      return 'mp3';
     }
 
     // Check bitDepth and samplingRate for lossless formats
@@ -78,12 +70,9 @@
       const rate = samplingRate || 44.1;
       return `${depth}-bit / ${rate} kHz`;
     }
-    if (tier === 'mp3-cd') {
+    if (tier === 'mp3') {
       const rate = samplingRate || 44.1;
-      return `${rate} kHz (Lossy)`;
-    }
-    if (tier === 'lossy') {
-      return '320 kbps';
+      return `${rate} kHz`;
     }
     return '16-bit / 44.1 kHz';
   });
@@ -92,8 +81,7 @@
     if (tier === 'max') return 'Hi-Res';
     if (tier === 'hires') return 'Hi-Res';
     if (tier === 'cd') return 'CD';
-    if (tier === 'mp3-cd') return 'MP3';
-    if (tier === 'lossy') return 'MP3';
+    if (tier === 'mp3') return 'MP3';
     return 'CD';
   });
 
@@ -101,8 +89,7 @@
   const iconPath = $derived.by(() => {
     if (tier === 'max' || tier === 'hires') return '/hi-res-gray.svg';
     if (tier === 'cd') return '/cd.svg';
-    if (tier === 'mp3-cd') return '/mp3-cd.svg';
-    if (tier === 'lossy') return '/mp3.svg';
+    if (tier === 'mp3') return '/mp3.svg';
     return '/cd.svg';
   });