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

• Reacted to PR Add reaction tools for issues and pull requests #2732 itself (:rocket:) via the consolidated add_issue_comment tool
• Opened this tracking issue
• React to this issue
• Comment on this issue
• React to that comment

Finding (pre-merge of #2732)

The consolidated toolset can react to issues/PRs and PR review comments, but there is currently no consolidated tool to react to a standalone issue comment by id. That specific capability is exactly what add_issue_comment_reaction in #2732 adds.

Filed automatically as part of a reactions smoke test.