feat: add customer session refresh functionality and improve session management

- Introduced RealtimeCustomerSessionRefreshPayload and RealtimeCustomerSessionRefreshEvent types for handling session refresh events.
- Updated ws_service to verify customer session and handle session refresh notifications.
- Enhanced API client to manage customer session tokens and expiration.
- Implemented customer session validation and storage in session storage.
- Added functions to exchange and ensure customer sessions.
- Updated IM real-time connection to include customer session tokens in WebSocket requests.
- Modified SDK and widget configurations to support external IDs and user tokens.

internal/controllers/api/customer_controller.go

@@ -0,0 +1,29 @@
+package api
+
+import (
+	"cs-agent/internal/pkg/openidentity"
+	"cs-agent/internal/services"
+
+	"github.com/kataras/iris/v12"
+	"github.com/mlogclub/simple/web"
+)
+
+type CustomerController struct {
+	Ctx iris.Context
+}
+
+func (c *CustomerController) PostSession_exchange() *web.JsonResult {
+	channel := services.ChannelService.GetEnabledChannel(c.Ctx)
+	if channel == nil {
+		return web.JsonErrorMsg("接入渠道不存在或已停用")
+	}
+	externalUser, err := openidentity.GetExternalUser(c.Ctx, services.ChannelService.GetUserTokenSecret(channel))
+	if err != nil {
+		return web.JsonError(err)
+	}
+	resp, err := services.CustomerSessionService.Exchange(channel, *externalUser)
+	if err != nil {
+		return web.JsonError(err)
+	}
+	return web.JsonData(resp)
+}