Reactions

Per-comment and per-discussion reactions.

📄️Get reaction counts for a comment

Returns aggregate counts grouped by `reaction_type` for a single comment. Read-only; safe for unauthenticated widget calls behind the API key.

📄️Toggle a reaction on a comment

End-user toggles a reaction type on a comment. Re-posting the same `reaction_type` removes the prior reaction; a different type replaces it. Emits a `reaction_toggled` SSE event.