feat: 添加历史会话模态框和更新组件

- 在 CoachScreen 中引入 HistoryModal 组件，优化历史会话展示
- 更新 NutritionRecordCard 组件，使用 Popover 替代 ActionSheet，提升操作体验
- 在 NutritionRecordsScreen 中引入 DateSelector 组件，简化日期选择逻辑
- 更新 package.json 和 package-lock.json，新增 react-native-popover-view 依赖
- 移除不再使用的历史会话模态框代码，提升代码整洁性

components/model/HistoryModal.tsx

@@ -0,0 +1,170 @@
+import { Ionicons } from '@expo/vector-icons';
+import React from 'react';
+import {
+  ActivityIndicator,
+  Modal,
+  ScrollView,
+  StyleSheet,
+  Text,
+  TouchableOpacity,
+  View,
+} from 'react-native';
+import dayjs from 'dayjs';
+
+import { AiConversationListItem } from '@/services/aiCoach';
+
+interface HistoryModalProps {
+  visible: boolean;
+  onClose: () => void;
+  historyLoading: boolean;
+  historyItems: AiConversationListItem[];
+  historyPage: number;
+  onRefreshHistory: (page: number) => void;
+  onSelectConversation: (id: string) => void;
+  onDeleteConversation: (id: string) => void;
+}
+
+export const HistoryModal: React.FC<HistoryModalProps> = ({
+  visible,
+  onClose,
+  historyLoading,
+  historyItems,
+  historyPage,
+  onRefreshHistory,
+  onSelectConversation,
+  onDeleteConversation,
+}) => {
+  return (
+    <Modal transparent visible={visible} animationType="fade" onRequestClose={onClose}>
+      <TouchableOpacity activeOpacity={1} style={styles.modalBackdrop} onPress={onClose}>
+        <View style={[styles.modalSheet, { backgroundColor: '#FFFFFF' }]}>
+          <View style={styles.modalHeader}>
+            <Text style={styles.modalTitle}>历史会话</Text>
+            <TouchableOpacity 
+              accessibilityRole="button" 
+              onPress={() => onRefreshHistory(historyPage)} 
+              style={styles.modalRefreshBtn}
+            >
+              <Ionicons name="refresh" size={16} color="#192126" />
+            </TouchableOpacity>
+          </View>
+          {historyLoading ? (
+            <View style={{ paddingVertical: 20, alignItems: 'center' }}>
+              <ActivityIndicator />
+              <Text style={{ marginTop: 8, color: '#687076' }}>加载中...</Text>
+            </View>
+          ) : (
+            <ScrollView style={{ maxHeight: 360 }}>
+              {historyItems.length === 0 ? (
+                <Text style={{ padding: 16, color: '#687076' }}>暂无会话</Text>
+              ) : (
+                historyItems.map((it) => (
+                  <View key={it.conversationId} style={styles.historyRow}>
+                    <TouchableOpacity
+                      style={{ flex: 1 }}
+                      onPress={() => onSelectConversation(it.conversationId)}
+                    >
+                      <Text style={styles.historyTitle} numberOfLines={1}>{it.title || '未命名会话'}</Text>
+                      <Text style={styles.historyMeta}>
+                        {dayjs(it.lastMessageAt || it.createdAt).format('YYYY/MM/DD HH:mm')}
+                      </Text>
+                    </TouchableOpacity>
+                    <TouchableOpacity 
+                      accessibilityRole="button" 
+                      onPress={() => onDeleteConversation(it.conversationId)} 
+                      style={styles.historyDeleteBtn}
+                    >
+                      <Ionicons name="trash-outline" size={16} color="#FF4444" />
+                    </TouchableOpacity>
+                  </View>
+                ))
+              )}
+            </ScrollView>
+          )}
+          <View style={styles.modalFooter}>
+            <TouchableOpacity 
+              accessibilityRole="button" 
+              onPress={onClose} 
+              style={styles.modalCloseBtn}
+            >
+              <Text style={{ color: '#192126', fontWeight: '600' }}>关闭</Text>
+            </TouchableOpacity>
+          </View>
+        </View>
+      </TouchableOpacity>
+    </Modal>
+  );
+};
+
+const styles = StyleSheet.create({
+  modalBackdrop: {
+    flex: 1,
+    backgroundColor: 'rgba(0,0,0,0.35)',
+    padding: 16,
+    justifyContent: 'flex-end',
+  },
+  modalSheet: {
+    borderTopLeftRadius: 16,
+    borderTopRightRadius: 16,
+    paddingHorizontal: 12,
+    paddingTop: 10,
+    paddingBottom: 12,
+  },
+  modalHeader: {
+    flexDirection: 'row',
+    alignItems: 'center',
+    justifyContent: 'space-between',
+    paddingHorizontal: 4,
+    paddingBottom: 8,
+  },
+  modalTitle: {
+    fontSize: 16,
+    fontWeight: '800',
+    color: '#192126',
+  },
+  modalRefreshBtn: {
+    width: 28,
+    height: 28,
+    borderRadius: 14,
+    alignItems: 'center',
+    justifyContent: 'center',
+    backgroundColor: 'rgba(0,0,0,0.06)'
+  },
+  historyRow: {
+    flexDirection: 'row',
+    alignItems: 'center',
+    paddingVertical: 10,
+    paddingHorizontal: 8,
+    borderRadius: 10,
+  },
+  historyTitle: {
+    fontSize: 15,
+    color: '#192126',
+    fontWeight: '600',
+  },
+  historyMeta: {
+    marginTop: 2,
+    fontSize: 12,
+    color: '#687076',
+  },
+  historyDeleteBtn: {
+    width: 28,
+    height: 28,
+    borderRadius: 14,
+    alignItems: 'center',
+    justifyContent: 'center',
+    backgroundColor: 'rgba(255,68,68,0.08)'
+  },
+  modalFooter: {
+    paddingTop: 8,
+    alignItems: 'flex-end',
+  },
+  modalCloseBtn: {
+    paddingHorizontal: 14,
+    paddingVertical: 8,
+    borderRadius: 10,
+    backgroundColor: 'rgba(0,0,0,0.06)'
+  },
+});
+
+export default HistoryModal;