Add comprehensive README and fix speaker entity in CLAUDE.md

Full documentation covering architecture, deployment, API endpoints,
speaker entity mapping, pipeline stages, and how recommendations
improve over time. Fixed stale speaker entity reference.

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

CLAUDE.md

@@ -40,7 +40,7 @@ curl http://192.168.86.51:8321/api/recommendations?limit=20
 # Generate and play a playlist
 curl -X POST http://192.168.86.51:8321/api/playlists/generate \
   -H "Content-Type: application/json" \
-  -d '{"total_tracks":20,"known_pct":30,"speaker_entity":"media_player.living_room_2","auto_play":true}'
+  -d '{"total_tracks":20,"known_pct":30,"speaker_entity":"media_player.living_room_speaker_2","auto_play":true}'
 ```
 
 ## Environment Variables