[codex] Add configurable password complexity checks

[btlqql]

Summary

• add configurable uppercase, lowercase, digit, and punctuation requirements to passwordcheck;
• expose four SUSET GUCs with strict defaults;
• cover enabled, disabled, and restored enforcement in both regression variants;
• document configuration and the plaintext-password limitation.

Repository placement

This is the clean Labs-targeted port of IvorySQL#1521. An IvorySQL maintainer requested moving the feature to IvorySQL-Labs because it extends PostgreSQL-native behavior and is not an Oracle-compatibility feature.

Validation

• the Labs commit has the same stable patch ID as the fully validated source commit 60dc6521a84c221bee9e114129edb5e2781b5680;
• the source patch passed build, Meson, contrib, PostgreSQL, Oracle/PostgreSQL, and Oracle regression workflows;
• git diff --check upstream/master...HEAD passed;
• the diff against Labs master contains one commit and only five intended files.

Refs IvorySQL#1102

Assisted-by: OpenAI:GPT-5

Percentage of AI-generated code: 100%