Task 1.4: Update provider classes to use key as primary identifier

- Enhanced download() method docstring in aniworld_provider.py
- Enhanced Download() method docstring in enhanced_provider.py
- Clarified that 'key' is the series unique identifier from provider
- Clarified that 'serie_folder'/'serieFolder' is filesystem folder name (metadata only)
- Added comprehensive Args, Returns, and Raises sections to docstrings
- Fixed PEP 8 line length issue in logging statement
- Verified existing code already uses 'key' for identification and logging
- All 34 provider-related tests pass successfully
- No functional changes required, documentation improvements only

src/core/SerieScanner.py

@@ -13,10 +13,7 @@ import uuid
 from typing import Callable, Iterable, Iterator, Optional
 
 from src.core.entities.series import Serie
-from src.core.exceptions.Exceptions import (
-    MatchNotFoundError,
-    NoKeyFoundException,
-)
+from src.core.exceptions.Exceptions import MatchNotFoundError, NoKeyFoundException
 from src.core.interfaces.callbacks import (
     CallbackManager,
     CompletionContext,