Add agent memory integrity fixtures

[jddark62]

Summary

• adds AG04 persistent memory evidence gates for write authorization, provenance chains, trust-tier retrieval, tamper evidence, TTL/review controls, quarantine semantics, and derived artifact cleanup
• adds a dedicated AG04 memory evidence review table and report fields so reviewers capture write sources, trust controls, remediation controls, and residual artifacts
• adds seven YAML fixtures covering pass, fail, and not-evaluable memory integrity cases

Validation

• git diff --check
• frontmatter parse check
• Markdown fence balance check
• YAML fixture parse check: 7 blocks
• required marker check for AG04-MEM-01 through AG04-MEM-07
• privacy marker scan

/claim #1374

Payment details can be coordinated privately after maintainer acceptance.