fix(worker): a corrupt/unreadable album no longer aborts the whole scan

Live-testing #9 surfaced a pre-existing gap: one truncated file mutagen chokes
on ("file said 4 bytes, read 0 bytes") raised out of _process_album and aborted
the entire library scan (worklist abandoned). Now scan_chunk catches a per-album
error, rolls back, logs it, counts it as skipped, marks the item done, and
continues — so a single bad file can't block the rest of the library.

worker tests: new case asserts a corrupt album is skipped while a good one still
imports (and captures its on-disk trackNames).

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

worker/lyra_worker/scan.py

@@ -169,7 +169,17 @@ def scan_chunk(conn: psycopg.Connection, resolver, probe: AudioProbe, browser,
     imported = skipped = 0
     browsed: set[str] = set()  # artists whose discography we've populated this chunk
     for item_id, artist_name, album_folder, album_path in items:
-        outcome = _process_album(conn, resolver, probe, browser, artist_name, album_folder, album_path, browsed)
+        try:
+            outcome = _process_album(conn, resolver, probe, browser, artist_name, album_folder, album_path, browsed)
+        except Exception as e:
+            # a single unreadable/corrupt album (e.g. a truncated file mutagen chokes on) must
+            # not abort the whole scan — skip it, mark it done, and keep going.
+            try:
+                conn.rollback()
+            except Exception:
+                pass
+            print(f"scan: skipping {artist_name}/{album_folder}: {e}", flush=True)
+            outcome = "skipped"
         if outcome == "imported":
             imported += 1
         elif outcome == "skipped":