ci: adopt AI review verdict suppression

[hln33]

Summary

Adopt aws/aws-durable-execution-ci#75 by pinning the AI-review caller to 8a06a1e5c82083a9224af9d489ddd030be44d978. Confirmed repeat findings are suppressed after a maintainer records deferred, false-positive, or out-of-scope. Other shared-CI callers remain unchanged.

Update .github/workflows/ai-pr-review.yml:21. Existing triggers, permissions, CodeBuild runner, prompt, and disabled Claude reviewer remain unchanged.

Validation

• git diff --check origin/main: passed.
• Actionlint 1.7.12: passed for the changed workflow.
• Eight local contract checks passed for this caller. Checks cover YAML parsing, the immutable pin, verdict/activity events, input types, nested permissions, secrets, reviewer enablement, and exact diff scope. The temporary validation suite passed 40/40 checks across all five consumers.