Add managed identity and PIM evidence gates to azure-review

[KooZuKi]

Summary

• add managed-identity and PIM effective-assignment review guidance
• add inherited scope, data-plane role, Key Vault authorization mode, workload identity, and audit evidence gates
• add identity report fields, severity guidance, references, and changelog entry

Validation

• git diff --check
• local frontmatter required-field check
• local prompt-injection pattern scan

Bounty

Addresses #1175. Preferred payment details can be provided privately after acceptance.