Album picker #730: drop the unused artist_name param (review cleanup)

Review caught that artist_name was added to pick_best_album_release's signature
and threaded through both call sites but never actually used — dead, misleading
code. Removed it from the helper + both callers. Artist-aware gating would be a
deliberate future feature (titles carry the artist inconsistently, so a hard
artist gate would risk the same false-negative class I just fixed); the album
relevance gate already resolves the reported wrong-release bug. No behavior
change. 127 plugin tests pass; compile + ruff clean.

core/download_plugins/album_bundle.py

@@ -171,7 +171,7 @@ def album_title_relevance(candidate_title: str, album_name: str) -> float:
 
 
 def pick_best_album_release(candidates, quality_guess,
-                            album_name: str = "", artist_name: str = "") -> Optional[object]:
+                            album_name: str = "") -> Optional[object]:
     """Pick the single best torrent / NZB for an album-bundle download.
 
     Heuristic, in priority order:

core/download_plugins/torrent.py

@@ -498,8 +498,7 @@ class TorrentDownloadPlugin(DownloadSourcePlugin):
             return result
 
         picked = pick_best_album_release(
-            candidates, _guess_quality_from_title,
-            album_name=album_name, artist_name=artist_name,
+            candidates, _guess_quality_from_title, album_name=album_name,
         )
         if picked is None:
             # No candidate matched the requested album (or none passed filtering).

core/download_plugins/usenet.py

@@ -469,8 +469,7 @@ class UsenetDownloadPlugin(DownloadSourcePlugin):
             return result
 
         picked = pick_best_album_release(
-            candidates, _guess_quality_from_title,
-            album_name=album_name, artist_name=artist_name,
+            candidates, _guess_quality_from_title, album_name=album_name,
         )
         if picked is None:
             # No candidate matched the requested album (or none passed filtering).