refactor(kb_utils): 简化文件路径处理逻辑

src/knowledge/kb_utils.py

@@ -49,8 +49,8 @@ def prepare_item_metadata(item: str, content_type: str, db_id: str) -> dict:
         file_path = Path(item)
         file_id = f"file_{hashstr(str(file_path) + str(time.time()), 6)}"
         file_type = file_path.suffix.lower().replace(".", "")
-        filename = os.path.relpath(file_path, Path.cwd())
-        item_path = str(file_path)
+        filename = file_path.name
+        item_path = os.path.relpath(file_path, Path.cwd())
     else:  # URL
         file_id = f"url_{hashstr(item + str(time.time()), 6)}"
         file_type = "url"