Add Bandcamp/YouTube links on all recs, Fix My Playlist, configurable rec count

- Bandcamp: match artist+song, fall back to artist-only page
- YouTube fallback: if not on Bandcamp, link to YouTube music video search
- Fix My Playlist: AI analyzes playlist, finds outliers, suggests replacements
- User chooses recommendation count (5, 10, 15, 20)

backend/app/services/bandcamp.py

@@ -26,6 +26,7 @@ async def search_bandcamp_verified(artist: str, title: str) -> dict | None:
     """Search Bandcamp and only return a result if the artist actually matches.
 
     Returns the best matching result or None if no good match found.
+    First tries artist+song, then falls back to artist-only search.
     """
     # Try track search first: "artist title"
     results = await search_bandcamp(f"{artist} {title}", item_type="t")
@@ -36,12 +37,12 @@ async def search_bandcamp_verified(artist: str, title: str) -> dict | None:
         if artist_sim >= 0.75 and title_sim >= 0.5:
             return r
 
-    # Try artist/band search as fallback — very strict matching
+    # Try artist/band search as fallback — return their artist page URL
     results = await search_bandcamp(artist, item_type="b")
     for r in results:
         # For band results, title IS the band name
         name = r.get("title", "") or r.get("artist", "")
-        if _similarity(name, artist) >= 0.8:
+        if _similarity(name, artist) >= 0.7:
             return r
 
     return None