Add Azure Key Vault evidence fixtures

[jddark62]

Summary

• adds a Key Vault effective evidence table for recovery and private-access scoring
• extends Section 8 with supplemental AZ-KV-REC-* and AZ-KV-NET-* checks for retention source, retention duration, purge protection, recovery operations, public network access, exception scope, private endpoint approval, private DNS, and client path evidence
• adds seven YAML fixtures covering private recoverable vaults, private endpoints with public access still enabled, missing private DNS, disabled purge protection with minimal retention, imported vault evidence gaps, scoped trusted-service exceptions, and pending private endpoints without client path evidence

Validation

• git diff --check
• frontmatter parse check
• Markdown fence balance check
• YAML fixture parse check: 7 blocks
• required marker check for AZ-KV-REC-01 through AZ-KV-REC-04 and AZ-KV-NET-01 through AZ-KV-NET-05
• privacy marker scan

/claim #999

Payment details can be coordinated privately after maintainer acceptance.