Initial commit: Set up Garmin Health Lab project structure

- Initialize monorepo with root workspace configuration
- Set up Express.js backend with TypeScript
- Set up React 18 frontend with TypeScript
- Create database schema with SQLite
- Implement project architecture and documentation
- Add development and deployment guidelines

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

client/src/components/Layout.tsx

@@ -0,0 +1,58 @@
+import React from 'react';
+import { Link, useLocation } from 'react-router-dom';
+import './Layout.css';
+
+interface LayoutProps {
+  children: React.ReactNode;
+}
+
+function Layout({ children }: LayoutProps) {
+  const location = useLocation();
+
+  const navigationItems = [
+    { path: '/', label: '仪表板', icon: '📊' },
+    { path: '/sync', label: '数据同步', icon: '🔄' },
+    { path: '/analysis', label: '数据分析', icon: '📈' },
+    { path: '/recommendations', label: '健康建议', icon: '💡' },
+    { path: '/settings', label: '设置', icon: '⚙️' },
+  ];
+
+  return (
+    <div className="layout">
+      <header className="header">
+        <div className="header-content">
+          <h1 className="logo">🏃 Garmin Health Lab</h1>
+          <p className="tagline">佳明健康数据分析平台</p>
+        </div>
+      </header>
+
+      <div className="container">
+        <nav className="sidebar">
+          <ul className="nav-list">
+            {navigationItems.map(item => (
+              <li key={item.path}>
+                <Link
+                  to={item.path}
+                  className={`nav-link ${location.pathname === item.path ? 'active' : ''}`}
+                >
+                  <span className="icon">{item.icon}</span>
+                  <span className="label">{item.label}</span>
+                </Link>
+              </li>
+            ))}
+          </ul>
+        </nav>
+
+        <main className="content">
+          {children}
+        </main>
+      </div>
+
+      <footer className="footer">
+        <p>© 2024 Garmin Health Lab. All rights reserved.</p>
+      </footer>
+    </div>
+  );
+}
+
+export default Layout;