Merge upstream/master and resolve conflicts

- Resolved conflict in dialog_settings.py (kept both cb_use_primary_album_artist and cb_mark_explicit checkboxes)
- Fixed code quality issues found by make check:
  * Removed duplicate on_download_album_from_track function (F811)
  * Updated isinstance calls to use X | Y syntax instead of (X, Y) (UP038)
  * Fixed unused loop variable album_stub (B007)
  * Applied automatic formatting fixes (black, prettier, trailing whitespace)
- Only remaining issue is C901 complexity warning in on_download_all_albums_from_playlist (expected per maintainer feedback)

tidal_dl_ng/model/cfg.py

@@ -12,7 +12,9 @@ class Settings:
     skip_existing: bool = True
     lyrics_embed: bool = False
     lyrics_file: bool = False
-    use_primary_album_artist: bool = False  # When True, uses first album artist instead of track artists for folder paths
+    use_primary_album_artist: bool = (
+        False  # When True, uses first album artist instead of track artists for folder paths
+    )
     # TODO: Implement API KEY selection.
     # api_key_index: bool = 0
     # TODO: Implement album info download to separate file.
@@ -36,6 +38,7 @@ class Settings:
     path_binary_ffmpeg: str = ""
     metadata_cover_dimension: CoverDimensions = CoverDimensions.Px320
     metadata_cover_embed: bool = True
+    mark_explicit: bool = False
     cover_album_file: bool = True
     extract_flac: bool = True
     downloads_simultaneous_per_track_max: int = 20
@@ -96,6 +99,7 @@ class HelpSettings:
         "The dimensions of the cover image embedded into the track. Possible values: 320x320, 640x640x 1280x1280."
     )
     metadata_cover_embed: str = "Embed album cover into file."
+    mark_explicit: str = "Mark explicit tracks with '🅴' in track title (only applies to metadata)."
     cover_album_file: str = "Save cover to 'cover.jpg', if an album is downloaded."
     extract_flac: str = "Extract FLAC audio tracks from MP4 containers and save them as `*.flac` (uses FFmpeg)."
     downloads_simultaneous_per_track_max: str = "Maximum number of simultaneous chunk downloads per track."