feat: add native player storyboard preview option

- Introduced `native_player_storyboard` setting with default disabled.
- Updated templates to conditionally load the storyboard preview script only for native players.
- Added descriptive comments for the new setting and template blocks.

settings.py

@@ -261,6 +261,17 @@ For security reasons, enabling this is not recommended.''',
         'category': 'interface',
     }),
 
+    ('native_player_storyboard', {
+        'type': bool,
+        'default': False,
+        'label': 'Storyboard preview (native)',
+        'comment': '''Show thumbnail preview on hover (native player modes).
+    Positioning is heuristic; may misalign in Firefox/Safari.
+    Works best on Chromium browsers.
+    No effect in Plyr.''',
+        'category': 'interface',
+    }),
+
     ('use_video_download', {
         'type': int,
         'default': 0,