fix(ci): authenticate CodeRabbit review requests as maintainer

[acgetchell]

Require CODERABBIT_REVIEW_TOKEN as a Dependabot secret so automated review comments use the maintainer identity CodeRabbit accepts. Fail closed for missing or unexpected credentials while keeping auto-merge on the scoped workflow token.

Summary by CodeRabbit

• Bug Fixes
  • Improved automated code review request handling.
  • Added validation for review credentials before submitting requests.
  • Prevented duplicate review comments and restricted comment matching to the intended author.
  • Reduced workflow permissions to improve security.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: ASSERTIVE

Plan: Pro

Run ID: cc9ae758-7757-42a5-a7dc-bb6636f69022

📥 Commits

Reviewing files that changed from the base of the PR and between 55d192d and 375c9ea.

📒 Files selected for processing (1)

• .github/workflows/dependabot-auto-merge.yml

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Walkthrough

The Dependabot auto-merge workflow now limits permissions and uses a validated CodeRabbit review token to find and create review-request comments through the GitHub API.

Changes

Dependabot review request hardening

Layer / File(s)	Summary
Workflow permissions and authenticated review requests .github/workflows/dependabot-auto-merge.yml	Removes issues: write, validates the configured token owner, filters marker comments by author, and posts review requests through the pull request issue-comments API.

Estimated code review effort: 2 (Simple) | ~10 minutes

Possibly related issues

• Automate Dependabot merges after CodeRabbit approval #131 — Both changes update the workflow’s CodeRabbit review-request step, including token handling and comment posting.

Possibly related PRs

• acgetchell/CDT-plusplus#133 — Both modify Dependabot auto-merge review gating, token usage, comment lookup, permissions, and API calls.

Poem

A guarded token takes the stage,
With tighter rights and API page.
Old comments filtered, duplicates flee,
Dependabot merges more carefully.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the CI authentication change for CodeRabbit review requests.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/coderabbit-review-token-auth

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