feat: add configurable category mappings for directory recognition

Allow users to configure multiple directory names per category (movie/series/anime) to support variations like "movies", "tv", "films". This enables proper categorization of files in directories that don't match the hardcoded singular forms, solving the issue where 635 files in "/mnt/Downloads/movies/" were incorrectly categorized as "other".

Configuration example:
  categories:
    movie: [movie, movies, films]
    series: [series, tv, shows]
    anime: [anime]

Changes include comprehensive validation, backward-compatible defaults, case-insensitive matching, and full test coverage (395 tests passing).

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/vlm/config.py

@@ -19,6 +19,7 @@ class Config:
         series_filename_template: Filename template for series (e.g., "S{season:02d}E{episode:02d}{ext}")
         log_level: Logging level (DEBUG, INFO, WARNING, ERROR, CRITICAL)
         quarantine_dir: Quarantine directory name relative to category root (e.g., ".quarantine")
+        categories: Mapping of category names to directory name lists for file categorization
     """
     library_root: Path
     video_extensions: list[str] = field(default_factory=lambda: [
@@ -30,6 +31,11 @@ class Config:
     series_filename_template: str = "S{season:02d}E{episode:02d}{ext}"
     log_level: str = "INFO"
     quarantine_dir: str = ".quarantine"
+    categories: dict[str, list[str]] = field(default_factory=lambda: {
+        "movie": ["movie"],
+        "series": ["series"],
+        "anime": ["anime"]
+    })
 
 
 def load_config(path: Path) -> Config:
@@ -79,7 +85,14 @@ def load_config(path: Path) -> Config:
     # Extract other settings
     quarantine_dir = data.get('quarantine_dir', '.quarantine')
     log_level = data.get('log_level', 'INFO')
-    
+
+    # Extract categories configuration
+    categories = data.get('categories', {
+        "movie": ["movie"],
+        "series": ["series"],
+        "anime": ["anime"]
+    })
+
     return Config(
         library_root=library_root,
         video_extensions=video_extensions,
@@ -88,7 +101,8 @@ def load_config(path: Path) -> Config:
         movie_filename_template=movie_filename_template,
         series_filename_template=series_filename_template,
         log_level=log_level,
-        quarantine_dir=quarantine_dir
+        quarantine_dir=quarantine_dir,
+        categories=categories
     )
 
 
@@ -110,7 +124,12 @@ def create_default_config(path: Path) -> Config:
         movie_filename_template="{title} ({year}){ext}",
         series_filename_template="S{season:02d}E{episode:02d}{ext}",
         log_level="INFO",
-        quarantine_dir=".quarantine"
+        quarantine_dir=".quarantine",
+        categories={
+            "movie": ["movie"],
+            "series": ["series"],
+            "anime": ["anime"]
+        }
     )
     
     # Create YAML content
@@ -124,7 +143,8 @@ def create_default_config(path: Path) -> Config:
             'series_filename': default_config.series_filename_template
         },
         'quarantine_dir': default_config.quarantine_dir,
-        'log_level': default_config.log_level
+        'log_level': default_config.log_level,
+        'categories': default_config.categories
     }
     
     # Ensure parent directory exists
@@ -204,5 +224,47 @@ def validate_config(config: Config) -> list[str]:
         errors.append("quarantine_dir must be a string")
     elif config.quarantine_dir.startswith('/') or config.quarantine_dir.startswith('\\'):
         errors.append("quarantine_dir must be relative to category root, not absolute")
-    
+
+    # Validate categories
+    if not config.categories:
+        errors.append("categories cannot be empty")
+    elif not isinstance(config.categories, dict):
+        errors.append("categories must be a dictionary")
+    else:
+        # Check required category keys exist
+        required_categories = {"movie", "series", "anime"}
+        missing = required_categories - set(config.categories.keys())
+        if missing:
+            errors.append(f"categories must include keys: {sorted(missing)}")
+
+        # Validate each category's directory list and check for duplicates
+        seen_dirs = {}
+        for category, dir_list in config.categories.items():
+            if not isinstance(dir_list, list):
+                errors.append(f"categories['{category}'] must be a list")
+                continue
+
+            if not dir_list:
+                errors.append(f"categories['{category}'] cannot be empty")
+                continue
+
+            for dir_name in dir_list:
+                if not isinstance(dir_name, str):
+                    errors.append(f"categories['{category}'] must contain strings")
+                    break
+
+                if not dir_name.strip():
+                    errors.append(f"categories['{category}'] contains empty directory name")
+                    break
+
+                # Check for duplicates (case-insensitive)
+                dir_lower = dir_name.lower()
+                if dir_lower in seen_dirs:
+                    errors.append(
+                        f"Duplicate directory name '{dir_name}' in categories "
+                        f"'{category}' and '{seen_dirs[dir_lower]}'"
+                    )
+                else:
+                    seen_dirs[dir_lower] = category
+
     return errors