- Add ChannelCapability.PROCESSING_STATUS and capability detection for supported channels
- Implement mark_message_processing_started/finished in Telegram, Slack, Discord, Feishu modules
- Telegram: manage typing lifecycle with max duration and explicit stop
- Slack: add/remove reaction as processing indicator
- Discord: start/stop typing indicator with async task management
- Feishu: add/remove reaction for processing status
- Refactor message chain to invoke processing status hooks for supported channels
- Ensure processing status is properly finished on sync and async message handling paths
- Add tests for processing status lifecycle and capability detection across channels
- Remove unused imports in anthropic.py, tmdbv3api/__init__.py, tv.py, test files
- Rename conflicting function names in subscribe.py and webhook.py
- Clean up unused re-exports in tmdbv3api/__init__.py (15 unused exports)
- Apply consistent formatting across API endpoints
- Enhance Feishu card builder to embed images using remote URLs or uploaded files
- Add logic to send image card first, then file attachment when both image and file are present
- Update card schema to 2.0 and use new button behaviors for callbacks and URLs
- Improve callback data extraction for both new and legacy card actions
- Extend tests to cover image embedding, mixed messages, and new card structure
