[Task] Add account expiry monitoring metrics for PostgreSQL

[turanalmammadov]

What does this PR do?

Adds account expiry monitoring metrics for PostgreSQL, consistent with the pattern already used for Oracle, MariaDB, SQL Server, and TiDB.

Changes

• app-postgresql.yml: Added new account_expiry metric set that queries pg_roles for roles with a non-null rolvaliduntil value. Exposes:

  • rolname – role (user) name
  • rolvaliduntil – account expiration timestamp
  • seconds_until_expiry – seconds remaining until expiry (negative means already expired)
  • rolcanlogin – whether the role is permitted to log in

• home/docs/help/postgresql.md: Added account_expiry metric set table (English)

• home/i18n/zh-cn/.../postgresql.md: Added account_expiry metric set table (Chinese)

Why is this needed?

Monitoring password/account expiration helps DBAs proactively detect accounts about to expire and avoid unexpected authentication failures in production systems.

Testing

SQL query tested against PostgreSQL 14+:

SELECT rolname, rolvaliduntil::text as rolvaliduntil,
       EXTRACT(EPOCH FROM (rolvaliduntil - now()))::bigint AS seconds_until_expiry,
       rolcanlogin::text as rolcanlogin
FROM pg_roles
WHERE rolvaliduntil IS NOT NULL
ORDER BY rolvaliduntil ASC;

Made with Cursor