Add Azure identity PIM fixtures

[jddark62]

Summary

• Adds managed identity, effective access, PIM, and Key Vault mode evidence gates to azure-review.
• Extends the Azure checklist with managed identity scope, effective assignments, PIM activation, Key Vault RBAC/access-policy mode, and workload federation evidence.
• Adds seven YAML edge-case fixtures covering benign Reader managed identity, high-impact Key Vault admin identity, PIM eligibility gaps, controlled PIM activation, inherited management-group roles, Key Vault access-policy mode, and federated workload credential risk.

Validation

• git diff --check
• Frontmatter YAML parse passed
• Fixture YAML parse passed: 7 blocks
• Markdown fence balance passed
• Required Azure identity/PIM markers present
• Microsoft reference URLs returned HTTP 200
• ASCII scan passed for new fixture file
• Privacy scan passed for public files

/claim #1175

Payment details can be coordinated privately after maintainer acceptance.