feat: 添加心情记录功能

在统计页面新增心情卡片和弹窗组件，支持用户记录和查看每日心情状态。

components/MoodCardCompact.tsx

@@ -0,0 +1,63 @@
+import React from 'react';
+import { StyleSheet, Text, TouchableOpacity, View } from 'react-native';
+
+interface MoodCardCompactProps {
+  onPress: () => void;
+}
+
+export function MoodCardCompact({ onPress }: MoodCardCompactProps) {
+  return (
+    <TouchableOpacity style={styles.container} onPress={onPress}>
+      <View style={styles.header}>
+        <Text style={styles.title}>心情</Text>
+      </View>
+
+      <View style={styles.content}>
+        <View style={styles.moodIcon}>
+          <Text style={styles.emoji}>😊</Text>
+        </View>
+        <Text style={styles.moodText}>记录今日心情</Text>
+      </View>
+    </TouchableOpacity>
+  );
+}
+
+const styles = StyleSheet.create({
+  container: {
+    backgroundColor: '#E8F5E8',
+    borderRadius: 16,
+    padding: 16,
+    minHeight: 100,
+  },
+  header: {
+    marginBottom: 8,
+  },
+  title: {
+    fontSize: 14,
+    fontWeight: '800',
+    color: '#192126',
+  },
+  content: {
+    flexDirection: 'row',
+    alignItems: 'center',
+    flex: 1,
+  },
+  moodIcon: {
+    width: 32,
+    height: 32,
+    borderRadius: 16,
+    backgroundColor: '#4CAF50',
+    justifyContent: 'center',
+    alignItems: 'center',
+    marginRight: 8,
+  },
+  emoji: {
+    fontSize: 16,
+  },
+  moodText: {
+    fontSize: 12,
+    color: '#2E7D32',
+    fontWeight: '600',
+    flex: 1,
+  },
+});