feat: wire the mutagen tagger into the worker loop

worker/lyra_worker/registry.py

@@ -1,4 +1,5 @@
 from lyra_worker._musicbrainz import MusicBrainzResolver
+from lyra_worker._mutagen import MutagenTagger
 from lyra_worker.adapters._slskd import SlskdClient
 from lyra_worker.adapters._streamrip import StreamripClient
 from lyra_worker.adapters._ytdlp import YtDlpClient
@@ -7,6 +8,7 @@ from lyra_worker.adapters.qobuz import QobuzAdapter
 from lyra_worker.adapters.soulseek import SoulseekAdapter
 from lyra_worker.adapters.youtube import YouTubeAdapter
 from lyra_worker.resolver import MbResolver
+from lyra_worker.tagger import Tagger
 
 
 def build_adapters(config: dict) -> list[SourceAdapter]:
@@ -26,3 +28,8 @@ def build_adapters(config: dict) -> list[SourceAdapter]:
 def build_resolver() -> MbResolver:
     """The MusicBrainz resolver used to canonicalize requests in intake."""
     return MusicBrainzResolver()
+
+
+def build_tagger() -> Tagger:
+    """The tagger that writes canonical metadata onto downloaded files."""
+    return MutagenTagger()