정렬 버튼을 그룹화

src/renderer/renderer.js

@@ -75,6 +75,8 @@ async function openFolder() {
   state.files.length = 0;
   state.files.push(...list);
   state.selectedIdxs.clear();
+  state.sortMode = 'name';
+  updateSortButtons();
   setStatus(`${state.files.length}개 파일 로드됨`, true);
 
   const folderName = folder.replace(/\\/g, '/').split('/').pop();
@@ -169,11 +171,18 @@ async function sortFiles(mode) {
   if (!state.files.length) return;
   if (mode === 'name') state.files.sort((a, b) => a.name.localeCompare(b.name, 'ko'));
   else                 state.files.sort((a, b) => a.mtime - b.mtime);
+  state.sortMode = mode;
   state.selectedIdxs.clear();
+  updateSortButtons();
   await renderGrid();
   setStatus(`${mode === 'name' ? '이름순' : '날짜순'}으로 정렬됨`, true);
 }
 
+function updateSortButtons() {
+  btnSortName.classList.toggle('active', state.sortMode === 'name');
+  btnSortDate.classList.toggle('active', state.sortMode === 'date');
+}
+
 // ── 미리보기 ─────────────────────────────────────
 function updatePreview() {
   const prefix = inputPrefix.value.trim() || 'photo';