close#16132
## Summary
This PR completes the Go-side merge and cleanup for chat channel APIs,
including handler/service wiring, route registration, and test coverage.
Implemented and aligned 5 chat channel APIs:
```
- POST `/api/v1/chat-channels`
- GET `/api/v1/chat-channels`
- GET `/api/v1/chat-channels/:channel_id`
- PATCH `/api/v1/chat-channels/:channel_id`
- DELETE `/api/v1/chat-channels/:channel_id`
```
Co-authored-by: Haruko386 <tryeverypossible@163.com>
## Changes
1. **Entity (`internal/entity/chat_channel.go`)**:
- Implemented `ChatChannel` struct mapping the `chat_channel` database
table.
- Declared `ChatChannelListResponse` as a DTO to filter out sensitive
credentials (`config` field) and fetch the associated `dialog_name` via
left join.
2. **GORM Migration (`internal/dao/database.go`)**:
- Registered `&entity.ChatChannel{}` in the `dataModels` array inside
`InitDB()` to enable safe GORM schema synchronization.
3. **DAO (`internal/dao/chat_channel.go`)**:
- Implemented `ChatChannelDAO` wrapping GORM CRUD methods (`Create`,
`GetByID`, `UpdateByID`, `DeleteByID`).
- Implemented `ListByTenantID` performing a `LEFT JOIN` on the `dialog`
table to retrieve `dialog_name` while excluding `config` values to avoid
credential leaks.
4. **Test (`internal/dao/chat_channel_test.go`)**:
- Added integration unit tests testing the full CRUD lifecycle and GORM
left-join mapping list querying.
