Expose four new MCP tools backed by existing DeckClient comment methods:
- deck_get_card_comments — list with limit/offset pagination
- deck_create_card_comment — top-level or threaded (via parent_id)
- deck_update_card_comment — author-only on the server
- deck_delete_card_comment — author-only, destructive, idempotent
Adds ListCardCommentsResponse and CardCommentOperationResponse models, and
extends the client unit tests to cover replies, deletion, pagination, and
the request shape for updates.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
