Feature request: endpoints for retrieving note comments and reactions

Summary

The @hackmd/api client currently has no methods for retrieving comment or reaction data from notes. The only comment-related field exposed is commentPermission (controlling who can comment), but the actual comment content, threads, and reactions are completely inaccessible via the API.

Request

Add API endpoints and corresponding client methods for retrieving comments and reactions:

Proposed endpoints

GET /v1/notes/:noteId/comments
GET /v1/notes/:noteId/reactions

Proposed client methods

// Get all comments on a note (including replies and reactions per comment)
async getComments(noteId: string): Promise<Comment[]>

// Get all reactions on a note
async getReactions(noteId: string): Promise<Reaction[]>

Suggested response types

interface Comment {
  id: string
  author: {
    id: string
    name: string
  }
  body: string
  createdAt: string  // ISO 8601
  updatedAt: string  // ISO 8601
  resolved: boolean
  range?: {
    startLine: number
    endLine: number
  }
  replies: Reply[]
  reactions: ReactionGroup[]
}

interface Reply {
  id: string
  author: {
    id: string
    name: string
  }
  body: string
  createdAt: string
}

interface ReactionGroup {
  emoji: string
  users: string[]  // user IDs
}

interface Reaction {
  noteId: string
  emoji: string
  user: {
    id: string
    name: string
  }
  createdAt: string
}

Motivation

HackMD's commenting and reaction features are valuable for collaboration, but teams that use the API or CLI to sync notes to external systems (e.g., GitHub repositories) lose all of this context. Exposing comment and reaction data via the API would enable:

• Backing up discussion context alongside note content
• Building integrations that preserve collaboration history
• Automating workflows that depend on comment/reaction data

Related

• Broader feature request: https://github.com/hackmdio/hackmd-io-issues/issues/428
• Original request from 2020: https://github.com/hackmdio/hackmd-io-issues/issues/207

No files or tests are named. Start by reviewing the existing @hackmd/api client methods and the related issues #428 and #207; the work is complete when the proposed comment and reaction endpoints, client methods, and response types are defined and supported.