docs: update deployment and test workflows to reflect cases 9 and 10 ...

- Added Case 9 (latency check) and Case 10 (node resync) to file_sync_tests table
- Updated deploy_to_production to reflect the 5 passing SmallFileSync cases rather than 4, and updated the execution time estimate from 60s down to 5s.

docs(workflows): add file_sync_tests workflow and enforce tests in deploy flow ...

- file_sync_tests.md: all-in-one commands, env var reference, test case table,
  and troubleshooting guide for the 8 file sync integration tests
- deploy_to_production.md: added mandatory pre-deploy gate (run SmallFileSync
  cases 1-4 before any commit to sync-related files) and mandatory post-deploy
  re-run of the same tests with rollback instruction if they fail