Replace the error-string-matching migration runner with a proper
schema_version table. Migrations are now numbered and recorded;
only unapplied versions run. Fresh databases seed at baseline
version (CREATE TABLE already includes all columns).
CREATE TABLE statements updated to include regions (sites) and
node_id (check_history) — previously only added via ALTER.
DeleteAlert now nulls sites.alert_id before deleting, preventing
dangling references that caused every incident to hit the error
path instead of alerting.
lerko
0974ab2b4c
