Series M reviewed, SYNC.php run clean, D680 broadcast picked up and actioned. No dev work.

Reviewed EXEC_OPEN_Tech_30_M.txt. Ran SYNC.php (all_clear=true). Picked up D680 broadcast (before/after-work discipline, verification-field requirement). Noted Builder's SYNC.php-timeout flag matches timeouts hit this session. Attempted handoff refresh via file_write_web.php directly - content verified written correctly on server but CHECKPOINT still showed stale 24.2h age, confirming CHECKPOINT tracks a DB timestamp set by CLOSE.php, not raw file mtime.