Fix CDDB album name extraction from header line

The header line can have a prefix before the dashes, e.g.:
  "#1 (Musicbrainz): ---- Artist / Album ----"
Use regex search for content between ---- markers instead of
stripping leading/trailing dashes from the full line.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/musiksammlung/ripper.py

@@ -207,10 +207,11 @@ def _stream_abcde(
             stripped_hdr = line.strip()
             print(f"\n  {stripped_hdr}", flush=True)
             # Album-Name zwischen den Strichen extrahieren (einmalig)
+            # Zeile z.B.: "#1 (Musicbrainz): ---- Artist / Album ----"
             if not detected_album:
-                inner = re.sub(r"^[-\s]+|[-\s]+$", "", stripped_hdr)
-                if inner:
-                    detected_album = inner
+                inner_m = re.search(r"-{2,}\s*(.+?)\s*-{2,}", stripped_hdr)
+                if inner_m:
+                    detected_album = inner_m.group(1).strip()
             continue
 
         # ── CDDB track lines  "1: Artist - Title"  or  "1: Artist / Title"