feat: 初始化项目基础架构和核心功能

- 添加项目基础结构：Cargo.toml、.gitignore、设备UID和密钥文件
- 实现前端Vue3项目结构：路由、登录页面、设备管理页面
- 添加核心协议定义(crates/protocol)：设备状态、资产、USB事件等
- 实现客户端监控模块：系统状态收集、资产收集
- 实现服务端基础API和插件系统
- 添加数据库迁移脚本：设备管理、资产跟踪、告警系统等
- 实现前端设备状态展示和基本交互
- 添加使用时长统计和水印功能插件

web/src/views/Settings.vue

@@ -0,0 +1,115 @@
+<template>
+  <div class="settings-page">
+    <el-row :gutter="20">
+      <el-col :span="12">
+        <el-card shadow="hover">
+          <template #header><span class="card-title">系统信息</span></template>
+          <el-descriptions :column="1" border size="small">
+            <el-descriptions-item label="系统版本">v{{ version }}</el-descriptions-item>
+            <el-descriptions-item label="数据库">{{ dbInfo }}</el-descriptions-item>
+            <el-descriptions-item label="在线终端">{{ health.connected_clients }}</el-descriptions-item>
+          </el-descriptions>
+        </el-card>
+
+        <el-card shadow="hover" style="margin-top: 20px">
+          <template #header><span class="card-title">修改密码</span></template>
+          <el-form :model="pwdForm" label-width="100px" size="small">
+            <el-form-item label="当前密码">
+              <el-input v-model="pwdForm.oldPassword" type="password" show-password />
+            </el-form-item>
+            <el-form-item label="新密码">
+              <el-input v-model="pwdForm.newPassword" type="password" show-password />
+            </el-form-item>
+            <el-form-item label="确认密码">
+              <el-input v-model="pwdForm.confirmPassword" type="password" show-password />
+            </el-form-item>
+            <el-form-item>
+              <el-button type="primary" @click="changePassword">修改密码</el-button>
+            </el-form-item>
+          </el-form>
+        </el-card>
+      </el-col>
+
+      <el-col :span="12">
+        <el-card shadow="hover">
+          <template #header><span class="card-title">数据维护</span></template>
+          <el-form label-width="100px" size="small">
+            <el-form-item label="历史数据">
+              <el-button @click="showRetentionInfo">查看保留策略</el-button>
+            </el-form-item>
+            <el-form-item label="数据库">
+              <el-button type="warning" @click="manualCleanup">手动清理</el-button>
+            </el-form-item>
+          </el-form>
+        </el-card>
+
+        <el-card shadow="hover" style="margin-top: 20px">
+          <template #header><span class="card-title">当前用户</span></template>
+          <el-descriptions :column="1" border size="small">
+            <el-descriptions-item label="用户名">{{ user.username }}</el-descriptions-item>
+            <el-descriptions-item label="角色">{{ user.role }}</el-descriptions-item>
+          </el-descriptions>
+        </el-card>
+      </el-col>
+    </el-row>
+  </div>
+</template>
+
+<script setup lang="ts">
+import { ref, reactive, onMounted } from 'vue'
+import { ElMessage } from 'element-plus'
+import { api } from '@/lib/api'
+
+const version = ref('0.1.0')
+const dbInfo = ref('SQLite (WAL mode)')
+const health = reactive({ connected_clients: 0, db_size_bytes: 0 })
+const user = reactive({ username: 'admin', role: 'admin' })
+
+const pwdForm = reactive({ oldPassword: '', newPassword: '', confirmPassword: '' })
+
+onMounted(() => {
+  // Decode username from JWT token
+  try {
+    const token = localStorage.getItem('token')
+    if (token) {
+      const payload = JSON.parse(atob(token.split('.')[1]))
+      user.username = payload.username || 'admin'
+      user.role = payload.role || 'admin'
+    }
+  } catch { /* ignore */ }
+
+  api.get<any>('/health')
+    .then((data: any) => {
+      if (data.version) version.value = data.version
+      health.connected_clients = data.connected_clients || 0
+      const bytes = data.db_size_bytes || 0
+      dbInfo.value = `SQLite (WAL mode) - ${(bytes / 1024 / 1024).toFixed(2)} MB`
+    })
+    .catch(() => { /* ignore */ })
+})
+
+function changePassword() {
+  if (pwdForm.newPassword !== pwdForm.confirmPassword) {
+    ElMessage.error('两次输入的密码不一致')
+    return
+  }
+  if (pwdForm.newPassword.length < 6) {
+    ElMessage.error('密码至少6位')
+    return
+  }
+  ElMessage.success('密码修改功能待实现')
+}
+
+function showRetentionInfo() {
+  ElMessage.info('数据保留策略在 config.toml 中配置')
+}
+
+function manualCleanup() {
+  ElMessage.warning('手动清理功能需通过服务器配置触发')
+}
+</script>
+
+<style scoped>
+.settings-page { padding: 20px; }
+.card-title { font-weight: 600; font-size: 15px; }
+</style>