Fix CDDB parser for compilations and add grab-progress fallback

- _parse_cddb_lines now handles both 'Artist - Title' and 'Artist / Title'
  (slash separator used by abcde for compilation albums like Various Artists)
- _stream_abcde collects grab-progress lines (track N: Artist / Title)
  as a fallback TrackInfo source when no CDDB lines are found
- New _parse_grab_tracks() splits grab titles on ' / ' into artist+title
- 5 new tests (TestParseCddbLines.test_compilation_slash_separator,
  TestParseGrabTracks.*)

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

tests/test_ripper.py

@@ -10,6 +10,7 @@ from musiksammlung.ripper import (
     _clean_input,
     _extract_tracks,
     _parse_cddb_lines,
+    _parse_grab_tracks,
     _rename_files,
     _sanitize_name,
     interactive_rip,
@@ -97,10 +98,55 @@ class TestParseCddbLines:
         tracks = _parse_cddb_lines(lines)
         assert len(tracks) == 1
 
+    def test_compilation_slash_separator(self) -> None:
+        """Kompilations-Format: 'N: Artist / Title' wird korrekt geparst."""
+        lines = [
+            "1: Trini Lopez / This Land Is Your Land (live)",
+            "2: The Foundations / In the Bad Bad Old Days",
+        ]
+        tracks = _parse_cddb_lines(lines)
+        assert len(tracks) == 2
+        assert tracks[0].artist == "Trini Lopez"
+        assert tracks[0].title == "This Land Is Your Land (live)"
+        assert tracks[1].artist == "The Foundations"
+        assert tracks[1].title == "In the Bad Bad Old Days"
+
     def test_empty_input(self) -> None:
         assert _parse_cddb_lines([]) == []
 
 
+class TestParseGrabTracks:
+    """Tests für _parse_grab_tracks."""
+
+    def test_artist_slash_title(self) -> None:
+        data = [(1, "Trini Lopez / This Land Is Your Land (live)")]
+        tracks = _parse_grab_tracks(data)
+        assert len(tracks) == 1
+        assert tracks[0].track_number == 1
+        assert tracks[0].artist == "Trini Lopez"
+        assert tracks[0].title == "This Land Is Your Land (live)"
+
+    def test_title_only_no_slash(self) -> None:
+        """Ohne Slash → leerer Künstler, Titel = gesamter String."""
+        data = [(3, "Beethoven 5. Sinfonie")]
+        tracks = _parse_grab_tracks(data)
+        assert tracks[0].artist == ""
+        assert tracks[0].title == "Beethoven 5. Sinfonie"
+
+    def test_multiple_tracks(self) -> None:
+        data = [
+            (1, "KC and the Sunshine Band / Give It Up"),
+            (2, "Sam & Dave / Can't You Find Another Way"),
+        ]
+        tracks = _parse_grab_tracks(data)
+        assert len(tracks) == 2
+        assert tracks[1].artist == "Sam & Dave"
+        assert tracks[1].title == "Can't You Find Another Way"
+
+    def test_empty_input(self) -> None:
+        assert _parse_grab_tracks([]) == []
+
+
 class TestRipperConfig:
     """Tests für RipperConfig."""