- Require valid RFC822.SIZE preflight metadata for every message before body FETCH
- Fail safely with HTTP 502 without body fetching on NO, malformed, or inconsistent sizes
- Distinguish missing mail (HTTP 404) from bad size preflight (HTTP 502)
- Discard duplicate IMAP response records for already-processed UIDs in batch loop
- Correct print notification toast to "Prepared N emails for printing; M unavailable"
- Add dedicated Playwright browser regression test script to repository test suite
- Add request-level tests for preflight NO, empty, partial, malformed, and duplicates