feat(library): replace/upgrade an owned album on demand

Add Request.force (migration add_request_force): the pipeline's intake now
skips the "already in library" dedupe for a forced job, so an owned album is
re-downloaded. The import step still keeps the new copy only when it's higher
quality, so a forced upgrade can never downgrade what's on disk.

- Worker: _is_force_job → dedupe bypassed when Request.force.
- POST /api/library/[id]/upgrade finds the matching MonitoredRelease and
  enqueues a force request (guards against stacking on an in-flight job).
- Library route exposes monitoredReleaseId; the album modal shows a
  "Replace / upgrade" button when a release exists.

Worker + web tests added (pipeline force re-acquire; upgrade route).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

worker/tests/conftest.py

@@ -56,13 +56,13 @@ def conn():
     connection.close()
 
 
-def insert_request(conn, artist="Artist", album="Album"):
+def insert_request(conn, artist="Artist", album="Album", force=False):
     """Insert a Request + its Job (state 'requested') and return the job id."""
     with conn.cursor() as cur:
         cur.execute(
-            'INSERT INTO "Request" (id, artist, album, status, "createdAt") '
-            "VALUES (gen_random_uuid()::text, %s, %s, 'pending', now()) RETURNING id",
-            (artist, album),
+            'INSERT INTO "Request" (id, artist, album, status, force, "createdAt") '
+            "VALUES (gen_random_uuid()::text, %s, %s, 'pending', %s, now()) RETURNING id",
+            (artist, album, force),
         )
         request_id = cur.fetchone()[0]
         cur.execute(