feat(admin): metadata-profile picker on integrations page

Persists the operator's metadata-profile choice alongside quality
profile + root folder. Defaults to the first profile Lidarr returns
(usually 'Standard' on a vanilla install) so the common case is
zero-click; operators with custom profiles like 'Singles only' can pick
explicitly.

Backend:
- Migration 0013: adds nullable default_metadata_profile_id to
  lidarr_config. Existing rows get NULL and the service falls back to
  fetch-and-pick-first until they save.
- Updated lidarr_config queries + sqlc + lidarrconfig.Config + admin
  view/put body to round-trip the new field.
- handlePutLidarrConfig requires it (along with QP and root folder)
  when enabled=true — matches the existing missing_defaults gate.
- New GET /api/admin/lidarr/metadata-profiles handler + lidarr.Client
  ListMetadataProfiles (GET /api/v1/metadataprofile, same shape as
  the quality-profile endpoint).
- lidarrrequests.Approve prefers cfg.DefaultMetadataProfileID; falls
  back to the fetch-list path only when 0 (back-compat for upgraders).

Frontend:
- LidarrConfig type + LidarrMetadataProfile type + qk.lidarrMetadataProfiles.
- listMetadataProfiles + createMetadataProfilesQuery client helpers.
- Integrations page: third <select> picker, auto-defaults to first
  profile when the saved value is 0, sends the new field on save and
  clears it on disconnect.
- Updated test fixtures + the duplicate 'Standard' option string in
  the dropdown-populates assertion.

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

internal/db/queries/lidarr_config.sql

@@ -1,17 +1,20 @@
 -- name: GetLidarrConfig :one
 SELECT id, enabled, base_url, api_key, default_quality_profile_id,
-       default_root_folder_path, created_at, updated_at
+       default_metadata_profile_id, default_root_folder_path,
+       created_at, updated_at
 FROM lidarr_config
 WHERE id = 1;
 
 -- name: UpdateLidarrConfig :one
 UPDATE lidarr_config
-   SET enabled                    = $1,
-       base_url                   = $2,
-       api_key                    = $3,
-       default_quality_profile_id = $4,
-       default_root_folder_path   = $5,
-       updated_at                 = now()
+   SET enabled                     = $1,
+       base_url                    = $2,
+       api_key                     = $3,
+       default_quality_profile_id  = $4,
+       default_metadata_profile_id = $5,
+       default_root_folder_path    = $6,
+       updated_at                  = now()
  WHERE id = 1
  RETURNING id, enabled, base_url, api_key, default_quality_profile_id,
-           default_root_folder_path, created_at, updated_at;
+           default_metadata_profile_id, default_root_folder_path,
+           created_at, updated_at;