Add config_local.py override pattern for sensitive settings

config.py now imports config_local.py at the bottom if present (gitignored).
Sensitive defaults (real archive passwords, personal tdl namespace) removed
from config.py and documented in config_local.py.example instead.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitignore

@@ -20,6 +20,7 @@ data/logs/
 
 # Env
 .env
+config_local.py
 
 # Python
 __pycache__/