debug: Add extensive logging for episode detection

Added detailed debug logging to diagnose why High Potential shows "0 episodes" despite having video files:

- Log season directory detection and pattern matching
- Log video file scanning and episode filename parsing
- Log season number extraction and matching logic
- Log final episode count and processing decisions

This will help identify where the episode detection is failing in the pipeline.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

core/episode_nfo_manager.py

@@ -19,23 +19,29 @@ class EpisodeNFOManager:
     def find_video_files_for_season(self, season_dir: Path) -> Dict[Tuple[int, int], List[Path]]:
         """Find all video files in season directory, grouped by (season, episode)"""
         if not season_dir.exists():
+            _log("DEBUG", f"Season directory does not exist: {season_dir}")
             return {}
         
         video_extensions = [".mkv", ".mp4", ".avi", ".mov", ".m4v"]
         episodes = {}
         
+        _log("DEBUG", f"Scanning video files in: {season_dir}")
         for video_file in season_dir.iterdir():
+            _log("DEBUG", f"Checking file: {video_file.name} (is_file: {video_file.is_file()}, suffix: {video_file.suffix.lower()})")
             if (video_file.is_file() and 
                 video_file.suffix.lower() in video_extensions):
                 
                 episode_info = self._parse_episode_from_filename(video_file.name)
+                _log("DEBUG", f"Episode parsing for '{video_file.name}': {episode_info}")
                 if episode_info:
                     season_num, episode_num = episode_info
                     key = (season_num, episode_num)
                     if key not in episodes:
                         episodes[key] = []
                     episodes[key].append(video_file)
+                    _log("DEBUG", f"Added video file: S{season_num:02d}E{episode_num:02d} → {video_file.name}")
         
+        _log("DEBUG", f"Total video files found: {len(episodes)} episodes")
         return episodes
     
     def _parse_episode_from_filename(self, filename: str) -> Optional[Tuple[int, int]]: