ui

# What does this PR do?


## Test Plan
# What does this PR do?


## Test Plan
# What does this PR do?


## Test Plan

llama_stack/ui/lib/auth.ts

@@ -0,0 +1,77 @@
+export interface User {
+  username: string;
+  email?: string;
+  name?: string;
+  avatar_url?: string;
+  organizations?: string[];
+}
+
+export interface AuthResponse {
+  access_token: string;
+  token_type: string;
+  expires_in: number;
+  user_info: User;
+}
+
+const TOKEN_KEY = "llama_stack_token";
+const USER_KEY = "llama_stack_user";
+
+export function getAuthToken(): string | null {
+  if (typeof window === "undefined") return null;
+  return localStorage.getItem(TOKEN_KEY);
+}
+
+export function setAuthToken(token: string): void {
+  if (typeof window !== "undefined") {
+    localStorage.setItem(TOKEN_KEY, token);
+  }
+}
+
+export function removeAuthToken(): void {
+  if (typeof window !== "undefined") {
+    localStorage.removeItem(TOKEN_KEY);
+  }
+}
+
+export function getStoredUser(): User | null {
+  if (typeof window === "undefined") return null;
+  const userStr = localStorage.getItem(USER_KEY);
+  if (!userStr) return null;
+  try {
+    return JSON.parse(userStr);
+  } catch {
+    return null;
+  }
+}
+
+export function setStoredUser(user: User): void {
+  if (typeof window !== "undefined") {
+    localStorage.setItem(USER_KEY, JSON.stringify(user));
+  }
+}
+
+export function removeStoredUser(): void {
+  if (typeof window !== "undefined") {
+    localStorage.removeItem(USER_KEY);
+  }
+}
+
+export function clearAuth(): void {
+  removeAuthToken();
+  removeStoredUser();
+}
+
+export function isAuthenticated(): boolean {
+  return !!getAuthToken();
+}
+
+export function isTokenExpired(token: string): boolean {
+  try {
+    const payload = JSON.parse(atob(token.split(".")[1]));
+    const exp = payload.exp;
+    if (!exp) return false;
+    return Date.now() >= exp * 1000;
+  } catch {
+    return true;
+  }
+}