feat: 모바일 일정 검색에 가상 스크롤 적용

- @tanstack/react-virtual useVirtualizer 적용
- 동적 높이 지원 (measureElement, data-index)
- SEARCH_LIMIT 10 → 20으로 증가
- 검색 결과가 많아도 DOM에는 화면에 보이는 요소만 렌더링

frontend/src/pages/mobile/public/Schedule.jsx

@@ -3,6 +3,7 @@ import { motion, AnimatePresence } from 'framer-motion';
 import { Clock, Tag, Link2, ChevronLeft, ChevronRight, ChevronDown, Search, X, Calendar } from 'lucide-react';
 import { useInfiniteQuery } from '@tanstack/react-query';
 import { useInView } from 'react-intersection-observer';
+import { useVirtualizer } from '@tanstack/react-virtual';
 import { getSchedules, getCategories, searchSchedules } from '../../../api/public/schedules';
 
 // 모바일 일정 페이지
@@ -26,7 +27,9 @@ function MobileSchedule() {
         setCalendarViewDate(newDate);
     };
     
-    const SEARCH_LIMIT = 10;
+    const SEARCH_LIMIT = 20; // 페이지당 20개
+    const ESTIMATED_ITEM_HEIGHT = 100; // 아이템 추정 높이 (동적 측정)
+    const scrollContainerRef = useRef(null); // 가상 스크롤 컨테이너
     const { ref: loadMoreRef, inView } = useInView({ threshold: 0, rootMargin: '100px' });
 
     // 검색 무한 스크롤
@@ -55,6 +58,14 @@ function MobileSchedule() {
         return searchData.pages.flatMap(page => page.schedules);
     }, [searchData]);
 
+    // 가상 스크롤 설정 (검색 모드에서만 활성화, 동적 높이 지원)
+    const virtualizer = useVirtualizer({
+        count: isSearchMode && searchTerm ? searchResults.length : 0,
+        getScrollElement: () => scrollContainerRef.current,
+        estimateSize: () => ESTIMATED_ITEM_HEIGHT,
+        overscan: 5, // 버퍼 아이템 수
+    });
+
     useEffect(() => {
         if (inView && hasNextPage && !isFetchingNextPage && isSearchMode && searchTerm) {
             fetchNextPage();
@@ -436,12 +447,11 @@ function MobileSchedule() {
             </AnimatePresence>
 
             {/* 컨텐츠 영역 */}
-            <div className="mobile-content" ref={contentRef}>
+            <div className="mobile-content" ref={isSearchMode && searchTerm ? scrollContainerRef : contentRef}>
             <div className="px-4 pt-4 pb-4">
                 {isSearchMode && searchTerm ? (
-                    // 검색 결과
-                    <div className="space-y-3">
-                        {searchLoading ? (
+                    // 검색 결과 - 가상 스크롤
+                    searchLoading ? (
                         <div className="flex justify-center py-8">
                             <div className="w-8 h-8 border-2 border-primary border-t-transparent rounded-full animate-spin" />
                         </div>
@@ -451,14 +461,42 @@ function MobileSchedule() {
                         </div>
                     ) : (
                         <>
-                                {searchResults.map((schedule, index) => (
+                            <div
+                                style={{
+                                    height: `${virtualizer.getTotalSize()}px`,
+                                    width: '100%',
+                                    position: 'relative',
+                                }}
+                            >
+                                {virtualizer.getVirtualItems().map((virtualItem) => {
+                                    const schedule = searchResults[virtualItem.index];
+                                    if (!schedule) return null;
+                                    
+                                    return (
+                                        <div
+                                            key={virtualItem.key}
+                                            ref={virtualizer.measureElement}
+                                            data-index={virtualItem.index}
+                                            style={{
+                                                position: 'absolute',
+                                                top: 0,
+                                                left: 0,
+                                                width: '100%',
+                                                transform: `translateY(${virtualItem.start}px)`,
+                                            }}
+                                        >
+                                            <div className={virtualItem.index < searchResults.length - 1 ? "pb-3" : ""}>
                                                 <ScheduleCard 
-                                        key={`${schedule.id}-search-${index}`}
                                                     schedule={schedule}
                                                     categoryColor={getCategoryColor(schedule.category_id)}
                                                     categories={categories}
                                                 />
-                                ))}
+                                            </div>
+                                        </div>
+                                    );
+                                })}
+                            </div>
+                            {/* 무한 스크롤 트리거 */}
                             <div ref={loadMoreRef} className="py-4">
                                 {isFetchingNextPage && (
                                     <div className="flex justify-center">
@@ -467,8 +505,7 @@ function MobileSchedule() {
                                 )}
                             </div>
                         </>
-                        )}
-                    </div>
+                    )
                 ) : loading ? (
                     <div className="flex justify-center py-8">
                         <div className="w-8 h-8 border-2 border-primary border-t-transparent rounded-full animate-spin" />