f187425835
ремонт: PG не отвечает 20+ мин, нужен диагностический workflow
Read-only SSH-based diagnostic for PG-not-accepting-connections incident:
systemctl/journalctl/df/free/uptime + tail /var/log/postgresql/postgresql-16-main.log
+ WAL size + dmesg + HTTPS probe of liderra.ru.
Triggered manually via gh workflow run pg-diagnose.yml.
No production mutations.
(Cherry-picked from feat/router-gate-hard-wall 8cbb84e1 — gh workflow run
requires file on default branch.)