Remove re-export shim from keycloak_auth.py, update consumer imports

- rbac_api.py: import get_current_user from auth.dependencies directly
- keycloak_auth.py: remove re-export of dependencies module symbols
- pdf_service.py, file_processor.py: remove misleading compat comments

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend-core/auth/keycloak_auth.py

@@ -374,13 +374,3 @@ class HybridAuthenticator:
         if self.keycloak_auth:
             await self.keycloak_auth.close()
 
-
-# Re-export factory functions and FastAPI dependencies from dependencies module
-# for backward compatibility with existing imports
-from .dependencies import (  # noqa: E402, F401
-    get_keycloak_config_from_env,
-    get_authenticator,
-    get_auth,
-    get_current_user,
-    require_role,
-)