feat: 添加会话列表和搜索功能，重构聊天界面组件

features/im/components/conversation-search-bar.tsx

@@ -0,0 +1,45 @@
+import MaterialIcons from "@expo/vector-icons/MaterialIcons";
+import { StyleSheet, TextInput, View } from "react-native";
+
+type ConversationSearchBarProps = {
+  value: string;
+  onChangeText: (value: string) => void;
+};
+
+export function ConversationSearchBar({
+  value,
+  onChangeText,
+}: ConversationSearchBarProps) {
+  return (
+    <View style={styles.wrapper}>
+      <MaterialIcons color="#A2A2A7" name="search" size={28} />
+      <TextInput
+        onChangeText={onChangeText}
+        placeholder="搜索联系人备注/昵称/ID"
+        placeholderTextColor="#B8B8BC"
+        style={styles.input}
+        value={value}
+      />
+    </View>
+  );
+}
+
+const styles = StyleSheet.create({
+  wrapper: {
+    alignItems: "center",
+    backgroundColor: "#F0F0F2",
+    borderCurve: "continuous",
+    borderRadius: 20,
+    flexDirection: "row",
+    gap: 8,
+    height: 52,
+    marginHorizontal: 20,
+    paddingHorizontal: 16,
+  },
+  input: {
+    color: "#2A2A2A",
+    flex: 1,
+    fontSize: 16,
+    fontWeight: "400",
+  },
+});