[aw] Prevent duplicate AI reviewer comments on reruns

[Ikuni17]

Summary

• Require Claude and Codex review runs to inspect prior review comments and reviews before reading the diff.
• Build a same-workflow prior-feedback index and suppress semantically equivalent findings on non-outdated, unchanged code, including resolved threads.
• Enrich prefetched review comments with the originating gh-aw workflow id, run id, and run URL so reviewers do not need to reconstruct identity from separate artifacts.

This addresses the repeated Claude Reviewer comments observed across multiple runs on #277679. The prefetched context was present in those runs, but the agent transcripts showed that Claude never opened pr-review-comments.json or pr-reviews.json.

Validation

• node --check .github/scripts/prefetch_pr_context.js
• node scripts/eslint .github/scripts/prefetch_pr_context.js
• Real PR payload smoke check for Claude workflow marker parsing
• git diff --check
• gh aw compile --purge --validate --no-check-update

The gh-aw compile completed successfully. No lock-file changes were produced because code-reviewer.md is imported at runtime.

Live validation

Dispatched Claude Reviewer twice from fix/claude-reviewer-repeated-comments against this unchanged draft PR:

• Run 30124161685
• Run 30125161491

In both runs:

• prefetch_pr_context completed successfully.
• The agent artifact contained both pr-review-comments.json and pr-reviews.json (both empty because this new PR had no reviews yet).
• Claude failed before its first model response or tool call, so it could not exercise the mandatory history read.
• The model gateway repeatedly returned HTTP 401 (invalid subscription key or wrong API endpoint) with intermittent HTTP 429 (No deployments available) for llm-gateway/claude-opus-4-8.
• No review comments or other safe outputs were posted.

The local context enrichment and branch-ref prefetch path are validated. Live verification that Claude reads prior comments and suppresses a duplicate remains blocked by the external model-gateway authentication/deployment failure.

[infra-vault-gh-plugin-prod]

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