feat: 优化 AI 教练聊天界面和个人信息页面

- 在 AI 教练聊天界面中添加消息自动滚动功能，提升用户体验
- 更新消息发送逻辑，确保新消息渲染后再滚动
- 在个人信息页面中集成用户资料拉取功能，支持每次聚焦时更新用户信息
- 修改登录页面，增加身份令牌验证，确保安全性
- 更新样式以适应新功能的展示和交互

app/ai-coach-chat.tsx

@@ -1,7 +1,7 @@
 import { Ionicons } from '@expo/vector-icons';
 import { BlurView } from 'expo-blur';
 import { useLocalSearchParams, useRouter } from 'expo-router';
-import React, { useMemo, useRef, useState } from 'react';
+import React, { useCallback, useEffect, useMemo, useRef, useState } from 'react';
 import {
   ActivityIndicator,
   FlatList,
@@ -49,6 +49,10 @@ export default function AICoachChatScreen() {
     content: `你好，我是你的普拉提教练 ${coachName}。可以向我咨询训练、体态、康复、柔韧等问题～`,
   }]);
   const listRef = useRef<FlatList<ChatMessage>>(null);
+  const [isAtBottom, setIsAtBottom] = useState(true);
+  const didInitialScrollRef = useRef(false);
+  const [composerHeight, setComposerHeight] = useState<number>(80);
+  const shouldAutoScrollRef = useRef(false);
 
   const planDraft = useAppSelector((s) => s.trainingPlan?.draft);
   const checkin = useAppSelector((s) => (s as any).checkin);
@@ -59,11 +63,35 @@ export default function AICoachChatScreen() {
     { key: 'analyze', label: '分析运动记录', action: () => handleAnalyzeRecords() },
   ], [router, planDraft, checkin]);
 
-  function scrollToEnd() {
+  const scrollToEnd = useCallback(() => {
     requestAnimationFrame(() => {
       listRef.current?.scrollToEnd({ animated: true });
     });
-  }
+  }, []);
+
+  const handleScroll = useCallback((e: any) => {
+    try {
+      const { contentOffset, contentSize, layoutMeasurement } = e.nativeEvent || {};
+      const paddingToBottom = 60;
+      const distanceFromBottom = (contentSize?.height || 0) - ((layoutMeasurement?.height || 0) + (contentOffset?.y || 0));
+      setIsAtBottom(distanceFromBottom <= paddingToBottom);
+    } catch { }
+  }, []);
+
+  useEffect(() => {
+    // 初次进入或恢复时，保持最新消息可见
+    scrollToEnd();
+  }, [scrollToEnd]);
+
+  // 取消对 messages.length 的全局监听滚动，改为在“消息实际追加完成”后再判断与滚动，避免突兀与多次触发
+
+  useEffect(() => {
+    // 输入区高度变化时，若用户在底部则轻柔跟随一次
+    if (isAtBottom) {
+      const id = setTimeout(scrollToEnd, 0);
+      return () => clearTimeout(id);
+    }
+  }, [composerHeight, isAtBottom, scrollToEnd]);
 
   async function fakeStreamResponse(prompt: string): Promise<string> {
     // 占位实现：模拟AI逐字输出（可替换为真实后端流式接口）
@@ -78,18 +106,22 @@ export default function AICoachChatScreen() {
   async function send(text: string) {
     if (!text.trim() || isSending) return;
     const userMsg: ChatMessage = { id: `u_${Date.now()}`, role: 'user', content: text.trim() };
+    // 标记：这次是新增消息，等内容真正渲染并触发 onContentSizeChange 时再滚动
+    shouldAutoScrollRef.current = isAtBottom;
     setMessages((m) => [...m, userMsg]);
     setInput('');
     setIsSending(true);
-    scrollToEnd();
+    // 立即滚动改为延后到 onContentSizeChange，避免突兀
 
     try {
       const replyText = await fakeStreamResponse(text.trim());
       const aiMsg: ChatMessage = { id: `a_${Date.now()}`, role: 'assistant', content: replyText };
+      // 同理：AI 消息到达时，与内容变化同步滚动
+      shouldAutoScrollRef.current = isAtBottom;
       setMessages((m) => [...m, aiMsg]);
-      scrollToEnd();
     } catch (e) {
       const aiMsg: ChatMessage = { id: `a_${Date.now()}`, role: 'assistant', content: '抱歉，请求失败，请稍后再试。' };
+      shouldAutoScrollRef.current = isAtBottom;
       setMessages((m) => [...m, aiMsg]);
     } finally {
       setIsSending(false);
@@ -195,13 +227,46 @@ export default function AICoachChatScreen() {
         data={messages}
         keyExtractor={(m) => m.id}
         renderItem={renderItem}
-        contentContainerStyle={{ paddingHorizontal: 14, paddingTop: 8, paddingBottom: insets.bottom + 140 }}
-        onContentSizeChange={scrollToEnd}
+        onLayout={() => {
+          // 确保首屏布局后也尝试滚动
+          if (!didInitialScrollRef.current) {
+            didInitialScrollRef.current = true;
+            setTimeout(scrollToEnd, 0);
+            requestAnimationFrame(scrollToEnd);
+          }
+        }}
+        contentContainerStyle={{ paddingHorizontal: 14, paddingTop: 8 }}
+        ListFooterComponent={() => (
+          <View style={{ height: insets.bottom + composerHeight + (isAtBottom ? 0 : 56) + 16 }} />
+        )}
+        onContentSizeChange={() => {
+          // 首次内容变化强制滚底，其余仅在接近底部时滚动
+          if (!didInitialScrollRef.current) {
+            didInitialScrollRef.current = true;
+            setTimeout(scrollToEnd, 0);
+            requestAnimationFrame(scrollToEnd);
+            return;
+          }
+          if (shouldAutoScrollRef.current) {
+            shouldAutoScrollRef.current = false;
+            setTimeout(scrollToEnd, 0);
+          }
+        }}
+        onScroll={handleScroll}
+        scrollEventThrottle={16}
         showsVerticalScrollIndicator={false}
       />
 
-      <KeyboardAvoidingView behavior={Platform.OS === 'ios' ? 'padding' : undefined} keyboardVerticalOffset={80}>
-        <BlurView intensity={18} tint={'light'} style={[styles.composerWrap, { paddingBottom: insets.bottom + 10 }]}>
+      <KeyboardAvoidingView behavior={Platform.OS === 'ios' ? 'padding' : 'height'} keyboardVerticalOffset={insets.top}>
+        <BlurView
+          intensity={18}
+          tint={'light'}
+          style={[styles.composerWrap, { paddingBottom: insets.bottom + 10 }]}
+          onLayout={(e) => {
+            const h = e.nativeEvent.layout.height;
+            if (h && Math.abs(h - composerHeight) > 0.5) setComposerHeight(h);
+          }}
+        >
           <View style={styles.chipsRow}>
             {chips.map((c) => (
               <TouchableOpacity key={c.key} style={[styles.chip, { borderColor: 'rgba(187,242,70,0.35)', backgroundColor: 'rgba(187,242,70,0.12)' }]} onPress={c.action}>
@@ -239,6 +304,16 @@ export default function AICoachChatScreen() {
           </View>
         </BlurView>
       </KeyboardAvoidingView>
+
+      {!isAtBottom && (
+        <TouchableOpacity
+          accessibilityRole="button"
+          onPress={scrollToEnd}
+          style={[styles.scrollToBottomFab, { bottom: insets.bottom + composerHeight + 16, backgroundColor: theme.primary }]}
+        >
+          <Ionicons name="chevron-down" size={18} color={theme.onPrimary} />
+        </TouchableOpacity>
+      )}
     </View>
   );
 }
@@ -347,6 +422,20 @@ const styles = StyleSheet.create({
     alignItems: 'center',
     justifyContent: 'center',
   },
+  scrollToBottomFab: {
+    position: 'absolute',
+    right: 16,
+    width: 40,
+    height: 40,
+    borderRadius: 20,
+    alignItems: 'center',
+    justifyContent: 'center',
+    shadowColor: '#000',
+    shadowOffset: { width: 0, height: 2 },
+    shadowOpacity: 0.15,
+    shadowRadius: 4,
+    elevation: 2,
+  },
 });