feat(history): add multi-account and WhatsApp foundation

src/app/store/auth.ts

@@ -2,7 +2,7 @@ import { create } from 'zustand'
 import { persist } from 'zustand/middleware'
 import type { AuthSession, Tenant, User } from '@/types'
 import type { RoleKey } from '@/config/roles'
-import { setTokenGetter } from '@/services/api/client'
+import { setTokenGetter, setUnauthorizedHandler } from '@/services/api/client'
 
 interface AuthState {
   token: string | null
@@ -32,6 +32,26 @@ export const useAuthStore = create<AuthState>()(
 
 // 让 API client 能读取 token（真实后端模式使用）
 setTokenGetter(() => useAuthStore.getState().token)
+setUnauthorizedHandler(() => {
+  useAuthStore.getState().logout()
+  if (!window.location.pathname.startsWith('/login')) {
+    window.location.replace('/login?reason=session-expired')
+  }
+})
+
+export function isSessionTokenExpired(token: string | null): boolean {
+  if (!token) return true
+  try {
+    const encoded = token.split('.')[1].replace(/-/g, '+').replace(/_/g, '/')
+    const padded = encoded.padEnd(Math.ceil(encoded.length / 4) * 4, '=')
+    const payload = JSON.parse(window.atob(padded)) as {
+      exp?: number
+    }
+    return !payload.exp || payload.exp * 1_000 <= Date.now()
+  } catch {
+    return true
+  }
+}
 
 export function useCurrentRole(): RoleKey {
   return useAuthStore((s) => s.user?.role ?? 'viewer')