feat(ui): add emoji picker with FlatList virtualization and improve input components

- Add full emoji picker with virtualized FlatList to CreatePostScreen and PostDetailScreen
- Add autoExpand prop to PostMentionInput for XHS-style content area
- Improve mention item styling with @ icon and hint text
- Fix HomeScreen tab switching race condition with requestAnimationFrame
- Fix PostRepository pagination to prefer cursor over page parameter
- Fix user store imports to use explicit UserManager path
- Refactor useCurrentUser hook to use sessionStore directly

src/components/business/PostMentionInput.tsx

@@ -13,6 +13,7 @@ import {
   StyleSheet,
   Platform,
 } from 'react-native';
+import { MaterialCommunityIcons } from '@expo/vector-icons';
 
 import Text from '../common/Text';
 import Avatar from '../common/Avatar';
@@ -35,6 +36,7 @@ interface PostMentionInputProps {
   maxLength?: number;
   style?: any;
   minHeight?: number;
+  autoExpand?: boolean;
 }
 
 const PostMentionInput: React.FC<PostMentionInputProps> = ({
@@ -45,6 +47,7 @@ const PostMentionInput: React.FC<PostMentionInputProps> = ({
   maxLength = 2000,
   style,
   minHeight = 100,
+  autoExpand = false,
 }) => {
   const colors = useAppColors();
   const currentUser = useAuthStore(s => s.currentUser);
@@ -180,16 +183,23 @@ const PostMentionInput: React.FC<PostMentionInputProps> = ({
     <TouchableOpacity
       style={[styles.mentionItem, { borderBottomColor: colors.divider }]}
       onPress={() => handleSelectMention(item)}
+      activeOpacity={0.7}
     >
-      <Avatar source={item.avatar} size={32} name={item.nickname} />
-      <Text style={[styles.mentionName, { color: colors.text.primary }]}>
-        {item.nickname}
-      </Text>
+      <Avatar source={item.avatar} size={36} name={item.nickname} />
+      <View style={styles.mentionInfo}>
+        <Text style={[styles.mentionName, { color: colors.text.primary }]}>
+          {item.nickname}
+        </Text>
+        <Text style={[styles.mentionHint, { color: colors.text.hint }]}>
+          点击提及
+        </Text>
+      </View>
+      <MaterialCommunityIcons name="at" size={18} color={colors.primary.main} />
     </TouchableOpacity>
   );
 
   return (
-    <View style={style}>
+    <View style={[styles.container, style]}>
       <TextInput
         ref={inputRef}
         value={value}
@@ -198,11 +208,15 @@ const PostMentionInput: React.FC<PostMentionInputProps> = ({
         placeholderTextColor={colors.text.hint}
         maxLength={maxLength}
         multiline
+        textAlignVertical="top"
+        scrollEnabled={!autoExpand}
         style={[
           styles.input,
+          autoExpand && styles.inputAutoExpand,
           {
             color: colors.text.primary,
-            backgroundColor: colors.background.default,
+            backgroundColor: autoExpand ? 'transparent' : colors.background.default,
+            minHeight,
           },
         ]}
       />
@@ -232,6 +246,9 @@ const PostMentionInput: React.FC<PostMentionInputProps> = ({
 };
 
 const styles = StyleSheet.create({
+  container: {
+    flexGrow: 1,
+  },
   input: {
     fontSize: fontSizes.md,
     padding: spacing.sm,
@@ -239,6 +256,12 @@ const styles = StyleSheet.create({
     minHeight: 100,
     textAlignVertical: 'top' as const,
   },
+  inputAutoExpand: {
+    borderRadius: 0,
+    paddingHorizontal: 0,
+    paddingTop: spacing.sm,
+    paddingBottom: spacing.sm,
+  },
   mentionPanel: {
     borderWidth: 1,
     borderRadius: borderRadius.md,
@@ -255,9 +278,18 @@ const styles = StyleSheet.create({
     paddingVertical: spacing.sm,
     borderBottomWidth: StyleSheet.hairlineWidth,
   },
+  mentionInfo: {
+    flex: 1,
+    marginLeft: spacing.sm,
+    justifyContent: 'center',
+  },
   mentionName: {
     fontSize: fontSizes.md,
-    marginLeft: spacing.sm,
+    fontWeight: '500',
+  },
+  mentionHint: {
+    fontSize: fontSizes.xs,
+    marginTop: 2,
   },
   emptyText: {
     fontSize: fontSizes.sm,