ci: add Bedrock AI pull request reviews

[zhongkechen]

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

Issue Link, if available

N/A

Description

• Add Claude and Codex pull request reviews through Amazon Bedrock.
• Check out only the trusted base SHA and build a complete, head-verified PR diff without executing proposed code.
• Run both reviewers as dedicated unprivileged users with read-only workspace access.
• Automatically review non-draft same-repository PRs and require ai-pr-review approval for drafts, Dependabot, and fork PRs.
• Retry failed or invalid review output once within bounded time limits and validate both reviewers against a shared JSON schema.
• Minimize superseded top-level summaries and Claude inline comments after posting a completed review.
• Share a Java SDK-specific review policy covering replay, serialization, concurrency, lifecycle, and API compatibility.
• Validate the review helpers and output schema in the existing Build workflow.

Repository setup after merge: restrict both environments to main, configure required reviewers on ai-pr-review, and set BEDROCK_ROLE_ARN on ai-pr-review-runtime.

Reference

• Original AI PR review workflow

Demo/Screenshots

N/A - GitHub Actions workflow change.

Checklist

• I have filled out every section of the PR template
• I have thoroughly tested this change

Testing

• actionlint 1.7.7 .github/workflows/build.yml .github/workflows/ai-pr-review.yml
• shellcheck 0.10.0 and bash -n for all four review helper scripts
• JSON schema parsing with jq -e
• YAML parsing for both modified workflows
• Structural diff against the latest conformance main workflow after repository-path adaptation
• Byte-for-byte comparison of post_ai_review_summary.sh with upstream
• Summary helper argument and inline-marker validation paths
• Live SHA-anchored context generation against PR test(conformance): add map 9-4 (empty items list) #556, confirming all reported changed files were collected

Unit Tests

Not applicable; no Java production code changed.

Integration Tests

The context-generation helper was exercised against a live pull request.

Examples

Not applicable.