expand acr and relational database depth

[TacoRocket]

What changed

• added narrow ACR management-plane depth for webhooks, replications, and policy posture
• expanded databases from Azure SQL-only coverage to a relational view spanning Azure SQL, PostgreSQL Flexible, and MySQL Flexible
• updated help text, operator narration, fixtures, goldens, and tests to match the new command behavior

Why it changed

• ACR needed operator-useful automation and governance cues without crossing into repository-content depth
• relational database triage needed to stop overfitting on Azure SQL so exposed PostgreSQL and MySQL targets are visible in the same command
• CCR follow-ups tightened partial-read honesty and output wording before publish

Impact

• operators now get more useful ACR posture signals in one pass
• azurefox databases now answers a relational-database question instead of only an Azure SQL question
• docs and tests now reflect the current command boundaries more accurately

Validation

• python3 -m ruff check src tests scripts
• PYTHONPATH=src python3 scripts/generate_schemas.py
• PYTHONPATH=src python3 -m pytest tests/test_collectors.py tests/test_golden_outputs.py tests/test_contract_schemas.py tests/test_cli_smoke.py tests/test_help.py tests/test_terminal_ux.py tests/test_models.py -q
• PYTHONPATH=src python3 -m pytest -q
• pre-push guardrail: PYTHONPATH=src git push -u origin review-followups-20260403