✨ feat: 应用界面重构 - 从模板中心到AI内容生成平台

- 重构首页：从模板列表展示改为AI功能展示界面
- 更新底部导航：将explore改为content，index改为home
- 新增多个页面：积分、兑换、历史记录、结果展示、设置等
- 优化UI组件：新增通用按钮、分类标签、加载状态等组件
- 清理冗余文件：删除旧的认证文档和积分详情页面
- 更新主题配置：调整配色方案和视觉风格
- 修复导入路径：优化组件导入结构

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

components/empty-state.tsx

@@ -0,0 +1,105 @@
+import React from 'react';
+import {
+  View,
+  StyleSheet,
+  TouchableOpacity,
+  ViewStyle,
+  StyleProp,
+} from 'react-native';
+import { ThemedText } from './themed-text';
+import { Colors, Spacing, BorderRadius, FontSize, Shadow } from '@/constants/theme';
+
+interface EmptyStateProps {
+  icon?: string;
+  title: string;
+  description?: string;
+  actionText?: string;
+  onAction?: () => void;
+  style?: StyleProp<ViewStyle>;
+}
+
+export function EmptyState({
+  icon = '📄',
+  title,
+  description,
+  actionText,
+  onAction,
+  style,
+}: EmptyStateProps) {
+  return (
+    <View style={[styles.container, style]}>
+      <View style={styles.content}>
+        <ThemedText style={styles.icon}>{icon}</ThemedText>
+
+        <ThemedText style={styles.title}>{title}</ThemedText>
+
+        {description ? (
+          <ThemedText style={styles.description}>
+            {description}
+          </ThemedText>
+        ) : null}
+
+        {actionText && onAction ? (
+          <TouchableOpacity
+            style={styles.actionButton}
+            onPress={onAction}
+            activeOpacity={0.8}
+          >
+            <ThemedText style={styles.actionText}>
+              {actionText}
+            </ThemedText>
+          </TouchableOpacity>
+        ) : null}
+      </View>
+    </View>
+  );
+}
+
+const styles = StyleSheet.create({
+  container: {
+    width: '100%',
+    height: '100%',
+    backgroundColor: Colors.background.secondary,
+    alignItems: 'center',
+    justifyContent: 'center',
+    paddingHorizontal: Spacing.xxl,
+  },
+  content: {
+    alignItems: 'center',
+    maxWidth: 280,
+  },
+  icon: {
+    fontSize: 48,
+    lineHeight: 64,
+    marginBottom: Spacing.lg,
+  },
+  title: {
+    fontSize: FontSize.md,
+    fontWeight: '600',
+    color: Colors.text.primary,
+    textAlign: 'center',
+    marginBottom: Spacing.sm,
+  },
+  description: {
+    fontSize: FontSize.sm,
+    color: Colors.text.tertiary,
+    textAlign: 'center',
+    lineHeight: 20,
+    marginBottom: Spacing.lg,
+  },
+  actionButton: {
+    backgroundColor: Colors.brand.primary,
+    paddingHorizontal: Spacing.xl,
+    paddingVertical: Spacing.md,
+    borderRadius: BorderRadius.md,
+    minWidth: 120,
+    alignItems: 'center',
+    justifyContent: 'center',
+    ...Shadow.small,
+  },
+  actionText: {
+    color: '#ffffff',
+    fontSize: FontSize.md,
+    fontWeight: '600',
+  },
+});