fix: scan records the probed format + skips hidden album dirs (probe once)

Probe each album exactly once and thread the ProbeResult through for
tags, quality, and format instead of hardcoding LibraryItem.format to
"FLAC" and re-probing on the tag-fallback path. Also skip album-level
directories starting with "." (previously only artist-level dirs were
skipped).

worker/lyra_worker/scan.py

@@ -28,7 +28,7 @@ def _first_audio(album_path: str) -> str | None:
     return None
 
 
-def _upsert(conn, target, quality_class: int, path: str) -> bool:
+def _upsert(conn, target, quality_class: int, fmt: str, path: str) -> bool:
     """Record have + monitored + followed for a resolved album. Returns True if newly imported."""
     with conn.cursor() as cur:
         watched_id = None
@@ -61,7 +61,7 @@ def _upsert(conn, target, quality_class: int, path: str) -> bool:
             '"qualityClass", "importedAt") '
             "VALUES (gen_random_uuid()::text, NULL, %s, %s, %s, 'scan', %s, %s, now()) "
             'ON CONFLICT (artist, album) DO NOTHING',
-            (target.artist, target.album, path, "FLAC", quality_class),
+            (target.artist, target.album, path, fmt, quality_class),
         )
         newly = cur.rowcount == 1  # a new LibraryItem means this album wasn't recorded before
     conn.commit()
@@ -81,21 +81,20 @@ def scan_library(conn: psycopg.Connection, resolver, probe: AudioProbe, dest_roo
             continue
         for album_folder in sorted(os.listdir(artist_path)):
             album_path = os.path.join(artist_path, album_folder)
-            if not os.path.isdir(album_path):
+            if album_folder.startswith(".") or not os.path.isdir(album_path):
                 continue
             audio = _first_audio(album_path)
             if audio is None:
                 continue  # no audio → not an album
+            pr = probe.probe(audio)
             album_name = _parse_album_dir(album_folder)
             target = resolver.resolve(artist_name, album_name) if artist_name and album_name else None
             if target is None:  # fall back to the file's embedded tags
-                pr = probe.probe(audio)
                 if pr.artist and pr.album and (pr.artist, pr.album) != (artist_name, album_name):
                     target = resolver.resolve(pr.artist, pr.album)
             if target is None:
                 skipped += 1
                 continue
-            q = probe.probe(audio).quality_class
-            if _upsert(conn, target, q, album_path):
+            if _upsert(conn, target, pr.quality_class, pr.fmt, album_path):
                 imported += 1
     return ScanResult(imported, skipped)