feat: 实现减脂体重管理App完整功能

- 实现拍照识别食物功能（集成大语言模型视觉能力）
- 实现智能对话功能（集成大语言模型流式输出）
- 实现食物记录和卡路里管理功能
- 实现体重记录和统计功能
- 实现健康数据管理页面
- 配置数据库表结构（用户、食物记录、体重记录）
- 实现Express后端API路由
- 配置Tab导航和前端页面
- 采用健康运动配色方案

client/constants/theme.ts

@@ -0,0 +1,177 @@
+export const Colors = {
+  light: {
+    textPrimary: "#1F2937",
+    textSecondary: "#6B7280",
+    textMuted: "#9CA3AF",
+    primary: "#059669", // Emerald-600 - 健康运动主色
+    accent: "#10B981", // Emerald-500 - 辅助色
+    success: "#10B981",
+    error: "#EF4444",
+    backgroundRoot: "#F8FAFC", // 冷瓷白
+    backgroundDefault: "#FFFFFF",
+    backgroundTertiary: "#F1F5F9",
+    buttonPrimaryText: "#FFFFFF",
+    tabIconSelected: "#059669",
+    border: "#E2E8F0",
+    borderLight: "#F1F5F9",
+  },
+  dark: {
+    textPrimary: "#F9FAFB",
+    textSecondary: "#9CA3AF",
+    textMuted: "#6B7280",
+    primary: "#34D399", // Emerald-400 - 暗色模式主色
+    accent: "#10B981",
+    success: "#34D399",
+    error: "#F87171",
+    backgroundRoot: "#111827", // 更深的背景色
+    backgroundDefault: "#1F2937",
+    backgroundTertiary: "#374151",
+    buttonPrimaryText: "#111827",
+    tabIconSelected: "#34D399",
+    border: "#374151",
+    borderLight: "#4B5563",
+  },
+};
+
+export const Spacing = {
+  xs: 4,
+  sm: 8,
+  md: 12,
+  lg: 16,
+  xl: 20,
+  "2xl": 24,
+  "3xl": 32,
+  "4xl": 40,
+  "5xl": 48,
+  "6xl": 64,
+};
+
+export const BorderRadius = {
+  xs: 4,
+  sm: 8,
+  md: 12,
+  lg: 16,
+  xl: 20,
+  "2xl": 24,
+  "3xl": 28,
+  "4xl": 32,
+  full: 9999,
+};
+
+export const Typography = {
+  display: {
+    fontSize: 112,
+    lineHeight: 112,
+    fontWeight: "200" as const,
+    letterSpacing: -4,
+  },
+  displayLarge: {
+    fontSize: 112,
+    lineHeight: 112,
+    fontWeight: "200" as const,
+    letterSpacing: -2,
+  },
+  displayMedium: {
+    fontSize: 48,
+    lineHeight: 56,
+    fontWeight: "200" as const,
+  },
+  h1: {
+    fontSize: 32,
+    lineHeight: 40,
+    fontWeight: "700" as const,
+  },
+  h2: {
+    fontSize: 28,
+    lineHeight: 36,
+    fontWeight: "700" as const,
+  },
+  h3: {
+    fontSize: 24,
+    lineHeight: 32,
+    fontWeight: "300" as const,
+  },
+  h4: {
+    fontSize: 20,
+    lineHeight: 28,
+    fontWeight: "600" as const,
+  },
+  title: {
+    fontSize: 18,
+    lineHeight: 24,
+    fontWeight: "700" as const,
+  },
+  body: {
+    fontSize: 16,
+    lineHeight: 24,
+    fontWeight: "400" as const,
+  },
+  bodyMedium: {
+    fontSize: 16,
+    lineHeight: 24,
+    fontWeight: "500" as const,
+  },
+  small: {
+    fontSize: 14,
+    lineHeight: 20,
+    fontWeight: "400" as const,
+  },
+  smallMedium: {
+    fontSize: 14,
+    lineHeight: 20,
+    fontWeight: "500" as const,
+  },
+  caption: {
+    fontSize: 12,
+    lineHeight: 16,
+    fontWeight: "400" as const,
+  },
+  captionMedium: {
+    fontSize: 12,
+    lineHeight: 16,
+    fontWeight: "500" as const,
+  },
+  label: {
+    fontSize: 14,
+    lineHeight: 20,
+    fontWeight: "500" as const,
+    letterSpacing: 2,
+    textTransform: "uppercase" as const,
+  },
+  labelSmall: {
+    fontSize: 12,
+    lineHeight: 16,
+    fontWeight: "500" as const,
+    letterSpacing: 1,
+    textTransform: "uppercase" as const,
+  },
+  labelTitle: {
+    fontSize: 14,
+    lineHeight: 20,
+    fontWeight: "700" as const,
+    letterSpacing: 2,
+    textTransform: "uppercase" as const,
+  },
+  link: {
+    fontSize: 16,
+    lineHeight: 24,
+    fontWeight: "400" as const,
+  },
+  stat: {
+    fontSize: 30,
+    lineHeight: 36,
+    fontWeight: "300" as const,
+  },
+  tiny: {
+    fontSize: 10,
+    lineHeight: 14,
+    fontWeight: "400" as const,
+  },
+  navLabel: {
+    fontSize: 10,
+    lineHeight: 14,
+    fontWeight: "500" as const,
+  },
+};
+
+export type Theme = typeof Colors.light;