feat: 初始化智能电量监控系统项目

该提交完成了完整的电费监控系统项目初始化，包含：
1.  后端Node.js+Express服务，支持定时采集、登录认证、数据API
2.  React前端界面，包含登录页和数据仪表盘
3.  Docker容器化配置和docker-compose部署文件
4.  环境变量示例和gitignore、dockerignore配置
5.  完整的项目文档README

client/src/pages/Login.jsx

@@ -0,0 +1,106 @@
+import { useState } from 'react';
+import { Card, Form, Input, Button, message } from 'antd';
+import { UserOutlined, LockOutlined } from '@ant-design/icons';
+import { Lightning } from '@icon-park/react';
+import { login } from '../api';
+
+export default function Login({ onLogin }) {
+  const [loading, setLoading] = useState(false);
+
+  const handleSubmit = async (values) => {
+    setLoading(true);
+    try {
+      const data = await login(values.username, values.password);
+      if (data.success) {
+        onLogin();
+      } else {
+        message.error(data.message || '用户名或密码错误');
+      }
+    } catch {
+      message.error('网络错误，请重试');
+    } finally {
+      setLoading(false);
+    }
+  };
+
+  return (
+    <div style={{
+      display: 'flex',
+      justifyContent: 'center',
+      alignItems: 'center',
+      minHeight: '100vh',
+      background: '#f5f7fa',
+      padding: 0,
+    }}>
+      <Card
+        style={{
+          width: '100%',
+          maxWidth: 400,
+          borderRadius: 12,
+          boxShadow: '0 2px 8px rgba(0,0,0,0.08)',
+        }}
+        styles={{ body: { padding: '48px 40px', textAlign: 'center' } }}
+      >
+        <div style={{ marginBottom: 32 }}>
+          <Lightning theme="filled" size="40" fill="#4a90e2" style={{ display: 'flex', justifyContent: 'center', marginBottom: 8 }} />
+          <h2 style={{
+            margin: 0,
+            fontSize: 24,
+            fontWeight: 600,
+            color: '#1a1a1a',
+          }}>
+            智能电量监控
+          </h2>
+          <p style={{ color: '#999', fontSize: 14, marginTop: 8, marginBottom: 0 }}>
+            请登录后查看用电数据
+          </p>
+        </div>
+
+        <Form
+          layout="vertical"
+          onFinish={handleSubmit}
+          autoComplete="off"
+        >
+          <Form.Item
+            name="username"
+            rules={[{ required: true, message: '请输入用户名' }]}
+          >
+            <Input
+              prefix={<UserOutlined style={{ color: '#999' }} />}
+              placeholder="用户名"
+              size="large"
+            />
+          </Form.Item>
+
+          <Form.Item
+            name="password"
+            rules={[{ required: true, message: '请输入密码' }]}
+          >
+            <Input.Password
+              prefix={<LockOutlined style={{ color: '#999' }} />}
+              placeholder="密码"
+              size="large"
+            />
+          </Form.Item>
+
+          <Form.Item style={{ marginTop: 32, marginBottom: 0 }}>
+            <Button
+              type="primary"
+              htmlType="submit"
+              loading={loading}
+              block
+              size="large"
+              style={{
+                height: 44,
+                fontWeight: 600,
+                fontSize: 16,
+              }}
+            >
+              登 录
+            </Button>
+          </Form.Item>
+        </Form>
+      </Card>
+    </div>
+  );
+}