feat(channel): Improve and Enrich Channel Implementation in Agent Service

**Background**

The basic channel functionality has been established in v2.0.6 (#1997), with support for Feishu and Discord channels. However, further improvements are needed, including:

- Add new channel support, initially planned for WeCom (企业微信) and DingTalk
- Improve existing implementations:
- `DiscordChannel`: add `list_tools` support to expose corresponding tools
- Feishu, DingTalk and other IM channels: support adding a channel by scanning a QR code instead of manually entering the app ID and secret key
- Integrate channel with scheduled tasks, enabling scheduled triggers to wake up an agent and complete corresponding tasks in the target channel

**Tasks**

- Add WeCom channel support
- Add DingTalk channel support
- `DiscordChannel`: implement `list_tools`
- QR code-based channel binding for IM channels (Feishu, DingTalk, etc.)
- Integrate channel with scheduled task mechanism

Start by locating the existing channel implementation layer (Discord and Feishu channels) and the channel registration/auth flow in the Agent Service. Next, inspect the IM channel binding path to add QR-code based onboarding and find where scheduled task triggers are dispatched to channels. Add WeCom and DingTalk as channel adapters in the same integration model, extend `DiscordChannel` with `list_tools`, and wire scheduled tasks to wake the target channel agent. The issue is done when these integrations are discoverable at runtime and scheduled triggers execute via the selected channel.

Escrita pelo modelo de indexação a partir do texto da issue.