fix: Add title enhancement for existing NFO files

- Modify extract_nfoguard_dates_from_episode_nfo() to detect missing titles
- Add enhance_existing_episode_nfo_with_title() method to update NFOs with titles
- Enhance Tier 1 processing to check for missing titles in existing NFO files
- Extract titles from filenames and update existing NFOs that lack title elements
- Fix NFO filename case to match S01E01.nfo format
- Preserves all existing NFO content while adding missing title elements

Addresses issue where existing NFO files with NFOGuard metadata were
skipping title extraction due to Tier 1 optimization caching.

nfoguard.py

@@ -623,6 +623,21 @@ class TVProcessor:
             source = nfo_data["source"] 
             aired = nfo_data.get("aired")
             
+            # Check if NFO is missing title and try to enhance it
+            if not nfo_data.get("has_title", False):
+                _log("INFO", f"NFO S{season_num:02d}E{episode_num:02d} missing title, attempting to extract from filename")
+                filename_title = self._extract_title_from_filename(season_path, season_num, episode_num)
+                if filename_title:
+                    enhanced = self.nfo_manager.enhance_existing_episode_nfo_with_title(
+                        season_path, season_num, episode_num, filename_title
+                    )
+                    if enhanced:
+                        _log("INFO", f"✅ Enhanced NFO S{season_num:02d}E{episode_num:02d} with title: '{filename_title}'")
+                    else:
+                        _log("WARNING", f"Failed to enhance NFO S{season_num:02d}E{episode_num:02d} with title")
+                else:
+                    _log("WARNING", f"Could not extract title from filename for S{season_num:02d}E{episode_num:02d}")
+            
             # Update file mtime if enabled (NFO is already correct)
             if config.fix_dir_mtimes and dateadded:
                 self.nfo_manager.set_file_mtime(episode_file, dateadded)