feat: add support for release channels in version upgrade and node agent updates

- Introduced ReleaseChannel type to manage stable and preview releases.
- Updated DashboardTopbar to handle version upgrades based on selected release channel.
- Enhanced node detail page to allow manual checks for agent updates on stable and preview channels.
- Modified API endpoints to support fetching and upgrading based on release channels.
- Updated UI components to reflect changes in version checking and upgrade processes.
- Added tests for new functionality related to preview releases and agent updates.

atsf_agent/internal/protocol/agent_api.go

@@ -19,6 +19,8 @@ type AgentSettings struct {
 	AutoUpdate        bool   `json:"auto_update"`
 	UpdateRepo        string `json:"update_repo"`
 	UpdateNow         bool   `json:"update_now"`
+	UpdateChannel     string `json:"update_channel"`
+	UpdateTag         string `json:"update_tag"`
 }
 
 type NodePayload struct {