bug: make syslog move/delete operations transactional to avoid partial state

[somethingwithproof]

Summary

Multiple move/delete flows perform separate INSERT/DELETE statements without transaction boundaries.

Evidence

functions.php:

• syslog_remove_items() around 613-623
• syslog_manage_items() around 1005-1015

Impact

On failures/crashes between statements, records can be partially moved/deleted, causing data inconsistency.

Expected fix

• Wrap coupled INSERT+DELETE operations in transactions
• Roll back on failure and log explicit error context