feat(feishu): add reaction support and group mention gating

[VanwaysAI]

Summary

Add Feishu reaction support for message processing status and group mention gating.

Features

Processing Status Indicators

• Add Typing reaction when receiving user messages (indicates processing)
• Remove Typing reaction after processing completes
• Add CrossMark reaction on processing failure

Group Chat Mention Gating

• Only respond to group messages when bot is @mentioned
• Fetch bot open_id via Bot Info API for accurate mention detection
• Avoid false triggers from mentions of other bots
• Private chat messages always respond

Reaction Event Subscriptions

• Subscribe to im.message.reaction.created_v1 and im.message.reaction.deleted_v1
• Support both Webhook and WebSocket event delivery
• Filter bot/app's own reactions to avoid feedback loops

Technical Details

New API Endpoints

• GET /open-apis/bot/v3/info - Fetch bot info (open_id)
• POST /open-apis/im/v1/messages/{message_id}/reactions - Add reaction
• DELETE /open-apis/im/v1/messages/{message_id}/reactions/{reaction_id} - Remove reaction

New Methods

• _fetchBotInfo() - Fetch bot open_id on startup
• _isMentioningBot() - Check if mentions include this bot
• _addReaction() / _removeReaction() - Manage reactions
• _onReactionEvent() - Handle incoming reaction events

Constants

const FEISHU_REACTION_IN_PROGRESS = "Typing";
const FEISHU_REACTION_FAILURE = "CrossMark";

Testing

• Typing reaction shown when processing messages
• Typing reaction removed after processing
• CrossMark reaction shown on failure
• Group messages without @mention are ignored
• Group messages with @mention are processed
• Private chat messages always processed
• Reaction events are received and logged

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Breaking Changes: None

Dependencies: None