feat(server/ops-api): add operations console backend

Stand up an internal ops-api service with operator account, auth, and
audit log subsystems backed by a dedicated migrations_ops migration set.
Wire Makefile targets and the migrate Dockerfile stage so the new schema
ships alongside the existing tenant + monitoring databases.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

server/migrations_ops/20260428100000_create_ops_schema.down.sql

@@ -0,0 +1,3 @@
+DROP TABLE IF EXISTS ops.audit_logs;
+DROP TABLE IF EXISTS ops.operator_accounts;
+DROP SCHEMA IF EXISTS ops;