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/test_pipeline.py

@@ -124,6 +124,25 @@ def test_dedupe_skips_already_in_library(conn):
         assert cur.fetchone()[0] == 1  # not duplicated
 
 
+def test_force_reacquires_an_album_already_in_library(conn):
+    # First acquisition puts the album in the library.
+    job1 = insert_request(conn, artist="Radiohead", album="In Rainbows")
+    claim_next(conn)
+    run_pipeline(conn, job1, [FakeQobuz()], dest_root="/tmp/lib")
+    # A forced re-acquire skips the dedupe → it searches + persists candidates again.
+    job2 = insert_request(conn, artist="Radiohead", album="In Rainbows", force=True)
+    claim_next(conn)
+    run_pipeline(conn, job2, [FakeQobuz()], dest_root="/tmp/lib", upgrade_cutoff=2)
+
+    assert _job_state(conn, job2) == ("imported", "import")
+    with conn.cursor() as cur:
+        cur.execute('SELECT count(*) FROM "Candidate" WHERE "jobId" = %s', (job2,))
+        assert cur.fetchone()[0] >= 1  # dedupe bypassed — it actually ran the search
+        cur.execute('SELECT count(*) FROM "LibraryItem" WHERE artist = %s AND album = %s',
+                    ("Radiohead", "In Rainbows"))
+        assert cur.fetchone()[0] == 1  # still not duplicated (keep-if-better import)
+
+
 def test_below_threshold_candidates_are_persisted_for_diagnosis(conn):
     from lyra_worker.adapters.fakes import FakeQobuz
     from lyra_worker.types import MBTarget