feat: 前端认证和工具模块

- 新增 useAuth.ts composable
- 新增 tools/useTools.ts
- 更新 Login.vue, Signup.vue

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

web/src/views/Login.vue

@@ -1,8 +1,11 @@
 <script setup lang="ts">
-import { ref } from 'vue'
-import { useRouter } from 'vue-router'
+import { ref, onMounted } from 'vue'
+import { useRouter, useRoute } from 'vue-router'
+import { useAuth } from '@/composables/useAuth'
 
 const router = useRouter()
+const route = useRoute()
+const { login } = useAuth()
 
 // 表单数据
 const username = ref('')
@@ -11,23 +14,38 @@ const rememberMe = ref(false)
 const isLoading = ref(false)
 const showPassword = ref(false)
 const errorMsg = ref('')
+const successMsg = ref('')
 
-// 模拟登录验证
-const handleLogin = () => {
+// 检查是否从注册页跳转过来
+onMounted(() => {
+  if (route.query.registered === 'true') {
+    successMsg.value = 'Account created successfully! Please sign in.'
+  }
+})
+
+// 登录处理
+const handleLogin = async () => {
   errorMsg.value = ''
 
-  if (username.value !== 'admin' || password.value !== 'admin') {
-    errorMsg.value = 'Invalid username or password'
+  if (!username.value || !password.value) {
+    errorMsg.value = 'Please enter username and password'
     return
   }
 
   isLoading.value = true
-  // 模拟登录
-  setTimeout(() => {
-    isLoading.value = false
+
+  try {
+    await login({
+      username: username.value,
+      password: password.value,
+    })
     // 登录成功，跳转到 Dashboard
-    router.push('/dashboard')
-  }, 1500)
+    router.push('/chat')
+  } catch (error: any) {
+    errorMsg.value = error.message || 'Login failed, please check your credentials'
+  } finally {
+    isLoading.value = false
+  }
 }
 </script>
 
@@ -52,6 +70,12 @@ const handleLogin = () => {
 
       <!-- 登录表单 -->
       <div class="bg-dark-700 rounded-2xl p-8 shadow-xl border border-dark-500/50">
+        <!-- 成功提示 -->
+        <div v-if="successMsg" class="mb-4 p-3 bg-green-500/10 border border-green-500/30 rounded-lg text-green-400 text-sm flex items-center gap-2">
+          <i class="fa-solid fa-check-circle"></i>
+          {{ successMsg }}
+        </div>
+
         <!-- 错误提示 -->
         <div v-if="errorMsg" class="mb-4 p-3 bg-red-500/10 border border-red-500/30 rounded-lg text-red-400 text-sm flex items-center gap-2">
           <i class="fa-solid fa-circle-exclamation"></i>