Add regression coverage for PR review path-resolution fallback

[Copilot]

GitHub can reject inline PR review comments with 422 "Path could not be resolved" in the same fallback family as "Line could not be resolved". This path-based variant was not covered by tests, leaving the safe-output body/partial-anchor fallback effectively unvalidated.

• What changed

  • Added a focused regression test in actions/setup/js/pr_review_buffer.test.cjs for a review submission that fails with:
    • message: "Path could not be resolved"
    • field: "comments[1].path"
  • The test verifies the existing fallback behavior:
    • resolvable comments are retried inline
    • the unresolvable comment is appended to the review body
    • the retry warning remains informative

• Why this matters

  • Covers the path-based 422 variant in the same reviewer fallback path as line-resolution failures
  • Reduces the chance of this class of API validation errors turning reviewer runs red without preserving review content

• Example scenario covered

  const unresolvedError = new Error('Unprocessable Entity: "Path could not be resolved"');
  unresolvedError.response = {
    data: {
      errors: [{ field: "comments[1].path", message: "Path could not be resolved" }],
    },
  };

• Fixes [deep-report] Broaden PR-review 422 fallback to match "Path could not be resolved" (pr_review_buffer.cjs:554) #47346

[Copilot]

Pull request overview

Adds regression coverage for indexed path-resolution failures during PR review submission.

Changes:

• Verifies resolvable comments remain inline.
• Verifies unresolvable path comments move to the review body.
• Confirms the retry warning remains informative.

Show a summary per file

File	Description
actions/setup/js/pr_review_buffer.test.cjs	Adds focused partial-anchor fallback coverage for path-resolution errors.

Review details

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• Files reviewed: 1/1 changed files
• Comments generated: 0
• Review effort level: Medium

[github-actions]

🎉 This pull request is included in a new release.

Release: v0.83.1