fix(lidarr): include artistName + metadataProfileId on add-artist/add-album

The 'lidarr_rejected' the operator was hitting on Approve was Lidarr 4xx-ing
the POST with two field-validation errors:

  'Metadata Profile Id' must be greater than '0'.
  'Artist Name' must not be empty.

Our payload was missing both. Lidarr's metadata profile is a separate
concept from quality profile (it controls which release types are
tracked: albums, singles, EPs, etc.) and is required by /api/v1/artist
and /api/v1/album. The 'already exists' line in the toast copy was an
incorrect guess at the cause; the real issue was an invalid payload.

Changes:

- internal/lidarr/types.go: AddArtistParams + AddAlbumParams gain
  ArtistName and MetadataProfileID. New MetadataProfile struct mirroring
  QualityProfile.
- internal/lidarr/client.go: AddArtist + AddAlbum payloads include both
  new fields. New ListMetadataProfiles fetches GET /api/v1/metadataprofile.
- internal/lidarrrequests/service.go: Approve fetches the metadata
  profile list and uses the first as a default (Lidarr installs ship
  'Standard' at id=1 OOB, so this works for vanilla setups). Picker
  on /admin/integrations is a follow-up. ArtistName flows from the
  request row.
- web/src/routes/admin/requests/+page.svelte: drop the
  speculative 'usually means already in library' copy on lidarr_rejected;
  point operators at server logs for the field-level reason instead.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

internal/lidarr/types.go

@@ -31,6 +31,16 @@ type QualityProfile struct {
 	Name string
 }
 
+// MetadataProfile controls which release types Lidarr tracks for an artist
+// (album / single / EP / compilation). It's a separate Lidarr concept from
+// quality profile and is required on POST /api/v1/artist — Lidarr 4xx's
+// the request with "'Metadata Profile Id' must be greater than '0'" if
+// it's missing or zero.
+type MetadataProfile struct {
+	ID   int
+	Name string
+}
+
 // RootFolder is the dropdown choice in /admin/integrations.
 type RootFolder struct {
 	Path       string
@@ -39,19 +49,28 @@ type RootFolder struct {
 }
 
 // AddArtistParams are the fields Lidarr requires on POST /api/v1/artist.
+// ArtistName and MetadataProfileID are both required; omitting either
+// produces a 400 with field-validation errors.
 type AddArtistParams struct {
-	ForeignArtistID  string
-	QualityProfileID int
-	RootFolderPath   string
-	MonitorAll       bool // true => monitor="all"; false => "future"
+	ForeignArtistID   string
+	ArtistName        string
+	QualityProfileID  int
+	MetadataProfileID int
+	RootFolderPath    string
+	MonitorAll        bool // true => monitor="all"; false => "future"
 }
 
 // AddAlbumParams are the fields Lidarr requires on POST /api/v1/album.
+// MetadataProfileID is included for the case where Lidarr has to create
+// the parent artist on the fly (when adding an album by an artist not
+// yet in the library).
 type AddAlbumParams struct {
-	ForeignAlbumID   string
-	ForeignArtistID  string // Lidarr requires the artist's foreign id too
-	QualityProfileID int
-	RootFolderPath   string
+	ForeignAlbumID    string
+	ForeignArtistID   string // Lidarr requires the artist's foreign id too
+	ArtistName        string
+	QualityProfileID  int
+	MetadataProfileID int
+	RootFolderPath    string
 }
 
 // PingResult is the response shape from GET /api/v1/system/status.