Add metadata saving functionality and enhance LoraCard with usage tips and notes

utils/file_utils.py

@@ -52,6 +52,8 @@ async def get_file_info(file_path: str) -> LoraMetadata:
         modified=os.path.getmtime(file_path),
         sha256=await calculate_sha256(file_path),
         base_model="Unknown",  # Will be updated later
+        usage_tips="",
+        notes="",
         from_civitai=True,
         preview_url=normalize_path(preview_url),
     )