rename media plugin to ytdlp with backwards-compatible aliases

- Rename archivebox/plugins/media/ → archivebox/plugins/ytdlp/
- Rename hook script on_Snapshot__63_media.bg.py → on_Snapshot__63_ytdlp.bg.py
- Update config.json: YTDLP_* as primary keys, MEDIA_* as x-aliases
- Update templates CSS classes: media-* → ytdlp-*
- Fix gallerydl bug: remove incorrect dependency on media plugin output
- Update all codebase references to use YTDLP_* and SAVE_YTDLP
- Add backwards compatibility test for MEDIA_ENABLED alias

archivebox/plugins/gallerydl/on_Snapshot__64_gallerydl.bg.py

@@ -59,7 +59,6 @@ def get_env_int(name: str, default: int = 0) -> int:
 
 
 STATICFILE_DIR = '../staticfile'
-MEDIA_DIR = '../media'
 
 def has_staticfile_output() -> bool:
     """Check if staticfile extractor already downloaded this URL."""
@@ -67,12 +66,6 @@ def has_staticfile_output() -> bool:
     return staticfile_dir.exists() and any(staticfile_dir.iterdir())
 
 
-def has_media_output() -> bool:
-    """Check if media extractor already downloaded this URL."""
-    media_dir = Path(MEDIA_DIR)
-    return media_dir.exists() and any(media_dir.iterdir())
-
-
 # Default gallery-dl args
 def get_gallerydl_default_args() -> list[str]:
     """Build default gallery-dl arguments."""
@@ -185,7 +178,7 @@ def main(url: str, snapshot_id: str):
             # Temporary failure (config disabled) - NO JSONL emission
             sys.exit(0)
 
-        # Check if staticfile or media extractors already handled this (permanent skip)
+        # Check if staticfile extractor already handled this (permanent skip)
         if has_staticfile_output():
             print(f'Skipping gallery-dl - staticfile extractor already downloaded this', file=sys.stderr)
             print(json.dumps({
@@ -195,15 +188,6 @@ def main(url: str, snapshot_id: str):
             }))
             sys.exit(0)
 
-        if has_media_output():
-            print(f'Skipping gallery-dl - media extractor already downloaded this', file=sys.stderr)
-            print(json.dumps({
-                'type': 'ArchiveResult',
-                'status': 'skipped',
-                'output_str': 'media already handled',
-            }))
-            sys.exit(0)
-
         # Get binary from environment
         binary = get_env('GALLERYDL_BINARY', 'gallery-dl')