Add DEMO feature to the project

frontend/src/api/client/apiClient.ts

@@ -45,6 +45,7 @@ class ApiClient {
   private baseURL: string;
   private authToken: string | null = null;
   private tenantId: string | null = null;
+  private demoSessionId: string | null = null;
   private refreshToken: string | null = null;
   private isRefreshing: boolean = false;
   private refreshAttempts: number = 0;
@@ -74,14 +75,31 @@ class ApiClient {
     // Request interceptor to add auth headers
     this.client.interceptors.request.use(
       (config) => {
-        if (this.authToken) {
+        // Public endpoints that don't require authentication
+        const publicEndpoints = [
+          '/demo/accounts',
+          '/demo/session/create',
+        ];
+
+        const isPublicEndpoint = publicEndpoints.some(endpoint =>
+          config.url?.includes(endpoint)
+        );
+
+        // Only add auth token for non-public endpoints
+        if (this.authToken && !isPublicEndpoint) {
           config.headers.Authorization = `Bearer ${this.authToken}`;
         }
-        
-        if (this.tenantId) {
+
+        if (this.tenantId && !isPublicEndpoint) {
           config.headers['X-Tenant-ID'] = this.tenantId;
         }
 
+        // Check demo session ID from memory OR localStorage
+        const demoSessionId = this.demoSessionId || localStorage.getItem('demo_session_id');
+        if (demoSessionId) {
+          config.headers['X-Demo-Session-Id'] = demoSessionId;
+        }
+
         return config;
       },
       (error) => {
@@ -317,6 +335,19 @@ class ApiClient {
     this.tenantId = tenantId;
   }
 
+  setDemoSessionId(sessionId: string | null) {
+    this.demoSessionId = sessionId;
+    if (sessionId) {
+      localStorage.setItem('demo_session_id', sessionId);
+    } else {
+      localStorage.removeItem('demo_session_id');
+    }
+  }
+
+  getDemoSessionId(): string | null {
+    return this.demoSessionId || localStorage.getItem('demo_session_id');
+  }
+
   getAuthToken(): string | null {
     return this.authToken;
   }