feat(stats): add sentence search tab and fix mining card behavior

- Add Search tab with realtime subtitle sentence search, media context, and mining actions
- Persist library card size selection across reloads
- Fix selection text written only for sentence cards, not word/audio cards
- Fix word mining audio routed to SentenceAudio field when present
- Fix sentence card created immediately before slow media generation completes
- Fix Anki config resolved at request time for sentence mining
- Prefer non-Signs/Songs tracks when auto-selecting secondary subtitle language

stats/src/components/vocabulary/pos-helpers.tsx

@@ -22,7 +22,7 @@ export function posColor(pos: string): string {
 
 export function PosBadge({ pos }: { pos: string }) {
   return (
-    <span className={`rounded-full px-2 py-0.5 text-[11px] font-medium ${posColor(pos)}`}>
+    <span className={`rounded-full px-2 py-0.5 text-[11px] font-medium whitespace-nowrap ${posColor(pos)}`}>
       {pos.replace(/_/g, ' ')}
     </span>
   );