✨ feat: 完整应用重构 - 优化界面架构与用户体验

主要变更：
- 重构应用界面：优化首页、登录、认证流程
- 新增用户档案模块：包含完整的档案管理组件
- 优化路由结构：重新组织页面布局和导航
- 改进API集成：新增活动、内容分类等API模块
- 删除冗余组件：清理不必要的文件和依赖

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

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

components/profile/profile-identity.tsx

@@ -0,0 +1,184 @@
+import React from 'react';
+import { View, TouchableOpacity, Image, type ImageSourcePropType } from 'react-native';
+import MaterialIcons from '@expo/vector-icons/MaterialIcons';
+
+import { ThemedText } from '@/components/themed-text';
+import { useColorScheme } from '@/hooks/use-color-scheme';
+import { deriveInitials, type IdentityStat } from '@/utils/profile-data';
+
+export function ProfileIdentity({
+  displayName,
+  avatarSource,
+  avatarSize,
+  stats,
+  onEdit,
+}: {
+  displayName: string;
+  avatarSource?: ImageSourcePropType;
+  avatarSize: number;
+  stats: IdentityStat[];
+  onEdit: () => void;
+}) {
+  const colorScheme = useColorScheme();
+  const palette = colorScheme === 'dark' ? darkPalette : lightPalette;
+
+  return (
+    <View style={styles.identityRow}>
+      <Avatar
+        palette={palette}
+        size={avatarSize}
+        source={avatarSource}
+        fallback={displayName}
+      />
+      <View style={styles.identityDetails}>
+        <View style={styles.nameRow}>
+          <ThemedText numberOfLines={1} style={[styles.username, { color: palette.textPrimary }]}>
+            {displayName}
+          </ThemedText>
+          <TouchableOpacity
+            onPress={onEdit}
+            activeOpacity={0.85}
+            style={[
+              styles.editButton,
+              {
+                borderColor: palette.border,
+                backgroundColor: palette.surface,
+              },
+            ]}
+          >
+            <MaterialIcons name="edit" size={16} color={palette.textPrimary} style={styles.editIcon} />
+            <ThemedText style={[styles.editLabel, { color: palette.textPrimary }]}>Edit</ThemedText>
+          </TouchableOpacity>
+        </View>
+        <View style={styles.statRow}>
+          {stats.map(stat => (
+            <StatItem key={stat.key} palette={palette} label={stat.label} value={stat.value} />
+          ))}
+        </View>
+      </View>
+    </View>
+  );
+}
+
+function Avatar({
+  palette,
+  size,
+  source,
+  fallback,
+}: {
+  palette: any;
+  size: number;
+  source?: ImageSourcePropType;
+  fallback: string;
+}) {
+  const initials = deriveInitials(fallback);
+  return (
+    <View
+      style={[
+        styles.avatarShell,
+        {
+          width: size,
+          height: size,
+          borderRadius: size / 2,
+          backgroundColor: palette.avatarBackdrop,
+        },
+      ]}
+    >
+      {source ? (
+        <Image source={source} style={{ width: size, height: size, borderRadius: size / 2 }} resizeMode="cover" />
+      ) : (
+        <ThemedText style={[styles.avatarInitials, { color: palette.textPrimary }]}>{initials}</ThemedText>
+      )}
+    </View>
+  );
+}
+
+function StatItem({ palette, label, value }: { palette: any; label: string; value: number }) {
+  return (
+    <View style={styles.statItem}>
+      <ThemedText style={[styles.statValue, { color: palette.textPrimary }]}>{value}</ThemedText>
+      <ThemedText style={[styles.statLabel, { color: palette.textSecondary }]}>{label}</ThemedText>
+    </View>
+  );
+}
+
+const darkPalette = {
+  textPrimary: '#F6F7FA',
+  textSecondary: '#8E9098',
+  avatarBackdrop: '#1F2026',
+  surface: '#121216',
+  border: '#1D1E24',
+};
+
+const lightPalette = {
+  textPrimary: '#0F1320',
+  textSecondary: '#5E6474',
+  avatarBackdrop: '#D5D8E2',
+  surface: '#FFFFFF',
+  border: '#E2E5ED',
+};
+
+const styles = {
+  identityRow: {
+    flexDirection: 'row' as const,
+    alignItems: 'center' as const,
+    marginBottom: 24,
+  },
+  avatarShell: {
+    alignItems: 'center' as const,
+    justifyContent: 'center' as const,
+  },
+  avatarInitials: {
+    fontSize: 28,
+    fontWeight: '700' as const,
+  },
+  identityDetails: {
+    flex: 1,
+    marginLeft: 18,
+  },
+  nameRow: {
+    flexDirection: 'row' as const,
+    alignItems: 'center' as const,
+    marginBottom: 10,
+  },
+  username: {
+    flex: 1,
+    fontSize: 20,
+    fontWeight: '700' as const,
+    marginRight: 12,
+  },
+  editButton: {
+    flexDirection: 'row' as const,
+    alignItems: 'center' as const,
+    borderRadius: 999,
+    borderWidth: 1,
+    paddingHorizontal: 20,
+    paddingVertical: 8,
+  },
+  editIcon: {
+    marginRight: 6,
+  },
+  editLabel: {
+    fontSize: 14,
+    fontWeight: '600' as const,
+  },
+  statRow: {
+    flexDirection: 'row' as const,
+    alignItems: 'center' as const,
+  },
+  statItem: {
+    flexDirection: 'row' as const,
+    alignItems: 'baseline' as const,
+    marginRight: 18,
+  },
+  statValue: {
+    fontSize: 15,
+    fontWeight: '700' as const,
+    marginRight: 4,
+  },
+  statLabel: {
+    fontSize: 13,
+    fontWeight: '500' as const,
+    textTransform: 'lowercase' as const,
+  },
+};