Track: reaction tools for issues and pull requests (#2732)

[SamMorrowDrums]

Tracking issue

Tracking the work in #2732 — "Add reaction tools for issues and pull requests" (by @timrogers, co-developed with Copilot).

Scope of #2732

• add_issue_reaction — react to an issue
• add_issue_comment_reaction — react to an issue comment
• add_pull_request_review_comment_reaction — react to a PR review comment

Why this tracking issue exists

Validating that reactions can be driven end-to-end through the consolidated issue tooling (add_issue_comment for issue/PR reactions, add_reply_to_pull_request_comment for PR review comment reactions).

Test performed via MCP (results)

• Reacted to PR Add reaction tools for issues and pull requests #2732 itself (:rocket:) via consolidated add_issue_comment — clean
• Opened this tracking issue — clean
• Reacted to this issue (:heart:) via consolidated add_issue_comment — clean
• Commented on this issue via consolidated add_issue_comment — clean
• React to that comment — not possible with the consolidated toolset ❌

Finding

The consolidated toolset reacts cleanly to issues / PRs (add_issue_comment) and to PR review comments (add_reply_to_pull_request_comment). However, there is no consolidated tool to react to a standalone issue comment by id. Attempting to route an issue-comment id through the PR-review-comment reaction tool hits POST /repos/.../pulls/comments/{id}/reactions and fails (403, wrong namespace).

This is exactly the gap add_issue_comment_reaction in #2732 closes. 👍 for shipping it.

Filed automatically as part of a reactions smoke test.

[SamMorrowDrums]

Smoke test comment 💬

This comment was added via the consolidated add_issue_comment tool to exercise the comment path. Next step in the test is to react to this comment — which is where the consolidated toolset currently has no issue-comment reaction tool (the add_issue_comment_reaction capability from #2732).