feat: hero player, LU/NOUVEAU badges, metadata resync, sticky mini-bar

- Refresh podcast title/author/imageUrl/description on RSS sync (fixes
  legacy 'Unknown Podcast' records)
- Always-visible Resync button on Library cards
- LU badge on completed episodes, NOUVEAU badge on <7-day-old episodes
- AudioPlayer gains mode='inline' that embeds in the Dashboard hero card
- Floating player suppressed on /dashboard to avoid dual audio
- Sticky mini-bar appears via IntersectionObserver when inline player
  scrolls out of view (shares the same <audio> element)
- Fix: 'Reprendre' button called undefined setSelectedEpisode; now calls
  playEpisode
- Add progress field to Episode TS interface

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

frontend/src/services/episodeService.ts

@@ -10,6 +10,10 @@ export interface Episode {
   duration: number;
   guid: string;
   imageUrl?: string;
+  progress?: {
+    position: number;
+    isCompleted: boolean;
+  } | null;
 }
 
 export interface EpisodeResponse {