Frontend update

client/src/contexts/AuthContext.jsx

@@ -0,0 +1,50 @@
+import { createContext, useContext, useEffect, useState, useCallback } from 'react'
+import { api } from '../api/client.js'
+
+const AuthContext = createContext(null)
+
+export function AuthProvider({ children }) {
+  const [user, setUser] = useState(null)
+  const [loading, setLoading] = useState(true)
+
+  const refresh = useCallback(async () => {
+    try {
+      const data = await api.me()
+      setUser(data.user)
+    } catch {
+      setUser(null)
+    } finally {
+      setLoading(false)
+    }
+  }, [])
+
+  useEffect(() => {
+    refresh()
+  }, [refresh])
+
+  const login = useCallback(async (username, password) => {
+    const data = await api.login(username, password)
+    setUser(data.user)
+    return data.user
+  }, [])
+
+  const logout = useCallback(async () => {
+    try {
+      await api.logout()
+    } finally {
+      setUser(null)
+    }
+  }, [])
+
+  return (
+    <AuthContext.Provider value={{ user, loading, login, logout, refresh }}>
+      {children}
+    </AuthContext.Provider>
+  )
+}
+
+export function useAuth() {
+  const ctx = useContext(AuthContext)
+  if (!ctx) throw new Error('useAuth must be used within AuthProvider')
+  return ctx
+}