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/services/file_processor.py

@@ -31,7 +31,6 @@ from .image_processing import ImageProcessor
 
 logger = logging.getLogger(__name__)
 
-# Re-export types for backward compatibility
 __all__ = [
     "FileType",
     "ProcessingMode",

backend-core/services/pdf_service.py

@@ -21,7 +21,6 @@ from jinja2 import Environment, FileSystemLoader, select_autoescape
 from weasyprint import HTML, CSS
 from weasyprint.text.fonts import FontConfiguration
 
-# Re-export models for backward compatibility
 from .pdf_models import (
     SchoolInfo,
     LetterData,