`metin-login-healthcheck.sh` is a root-only operational check for the Debian VPS.

What it does:
- creates a temporary account in MariaDB
- runs `metin_login_smoke` against auth and channel ports
- verifies `AUTH_SUCCESS`, `EMPIRE`, and `LOGIN_SUCCESS4`
- deletes the temporary account on exit

Default paths and ports are tuned for the current VPS layout. Override with env vars if needed:
- `RUN_AS_USER`
- `SERVER_HOST`
- `AUTH_PORT`
- `CHANNEL_PORT`
- `SMOKE_BIN`
