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.

web/lib/stores/kefu-chat.ts

@@ -5,12 +5,14 @@ import { create } from "zustand"
 import {
   closeImConversation,
   createOrMatchImConversation,
+  ensureCustomerSession,
   fetchImMessages,
   fetchImWidgetConfig,
   markImMessageRead,
   sendImMessage,
   uploadImAttachment,
   uploadImImage,
+  applyCustomerSessionRefresh,
   type ImAsset,
   type ImConversation,
   type ImMessage,
@@ -159,11 +161,17 @@ export const useKefuChatStore = create<KefuChatStore>((set, get) => {
         return
       }
 
+      const payload = event.data ?? event.payload
+      if (event.type === "customer_session.refresh") {
+        applyCustomerSessionRefresh(payload)
+        return
+      }
+
       const conversationId = get().conversation?.id
       if (!conversationId) {
         return
       }
-      const payload = event.data ?? event.payload
+
       if (event.type === "resyncRequired") {
         void get().refreshMessages()
         return
@@ -281,6 +289,11 @@ export const useKefuChatStore = create<KefuChatStore>((set, get) => {
             themeColor: widgetConfig.themeColor || "#2563eb",
           })
 
+          await ensureCustomerSession()
+          if (bootstrapToken !== token || !get().isOpen) {
+            return
+          }
+
           let currentConversation = get().conversation
           if (!get().initialized || !currentConversation) {
             currentConversation = await createOrMatchImConversation()