Fix FileNotFoundError handling in rename_file methods

- Add FileNotFoundError exception handling to both sync and async rename_file methods
- Return HTTP 404 error instead of generic 500 error when file/directory doesn't exist
- Improves error specificity for file rename operations

Author: aws-jasakshi

jupyter_server/services/contents/filemanager.py

@@ -602,6 +602,8 @@ def rename_file(self, old_path, new_path):
                 shutil.move(old_os_path, new_os_path)
         except web.HTTPError:
             raise
+        except FileNotFoundError:
+            raise web.HTTPError(404, "File or directory does not exist: %s" % old_path)
         except Exception as e:
             raise web.HTTPError(500, f"Unknown error renaming file: {old_path} {e}") from e
 
@@ -1069,6 +1071,8 @@ async def rename_file(self, old_path, new_path):
                 await run_sync(shutil.move, old_os_path, new_os_path)
         except web.HTTPError:
             raise
+        except FileNotFoundError:
+            raise web.HTTPError(404, "File or directory does not exist: %s" % old_path)
         except Exception as e:
             raise web.HTTPError(500, f"Unknown error renaming file: {old_path} {e}") from e