[lijiashu1]

Summary

• Write room/session state to a unique temporary file before replacing the persisted JSON file.
• Use a same-directory rename so a process interruption during serialization/write does not truncate the last valid database file.
• Clean up the temporary file if writing or replacement fails, and use restrictive permissions for the temporary data file.

Validation

• Reviewed the change against the existing synchronous persistence path.
• Automated tests were not run in this workflow.