fix(pop): POP 화면 관리 좌측 패널 UX 개선 (스크롤 + 접기/펼치기)

- 좌측 패널 스크롤 수정: 부모에 overflow-hidden, ScrollArea에 min-h-0
  추가하여 미분류 목록이 많을 때 스크롤바가 정상 작동하도록 개선
- 카테고리 그룹 기본 접힌 상태: loadGroups 자동 확장 로직 제거하여
  페이지 진입 시 깔끔한 트리 뷰 제공
- 미분류 회사코드별 접기/펼치기: 최고관리자/COMPANY_7 등 회사코드
  그룹마다 토글 헤더 추가, 항목 수 Badge 표시

frontend/app/(main)/admin/screenMng/popScreenMngList/page.tsx

@@ -285,7 +285,7 @@ export default function PopScreenManagementPage() {
       ) : (
         <div className="flex-1 overflow-hidden flex">
           {/* 왼쪽: 카테고리 트리 + 화면 목록 */}
-          <div className="w-[320px] min-w-[280px] max-w-[400px] flex flex-col border-r bg-background">
+          <div className="w-[320px] min-w-[280px] max-w-[400px] flex flex-col border-r bg-background overflow-hidden">
             {/* 검색 */}
             <div className="shrink-0 p-3 border-b">
               <div className="relative">

frontend/components/pop/management/PopCategoryTree.tsx

@@ -499,6 +499,9 @@ export function PopCategoryTree({
   const [movingFromGroupId, setMovingFromGroupId] = useState<number | null>(null);
   const [moveSearchTerm, setMoveSearchTerm] = useState("");
 
+  // 미분류 회사코드별 접기/펼치기
+  const [expandedCompanyCodes, setExpandedCompanyCodes] = useState<Set<string>>(new Set());
+
   // 화면 맵 생성 (screen_id로 빠르게 조회)
   const screensMap = useMemo(() => {
     const map = new Map<number, ScreenDefinition>();
@@ -517,14 +520,6 @@ export function PopCategoryTree({
       // 그룹 목록 조회
       const data = await getPopScreenGroups(searchTerm);
       setGroups(data);
-
-      // 첫 로드 시 루트 그룹들 자동 확장
-      if (expandedGroups.size === 0 && data.length > 0) {
-        const rootIds = data
-          .filter((g) => g.hierarchy_path === "POP" || g.hierarchy_path?.split("/").length === 2)
-          .map((g) => g.id);
-        setExpandedGroups(new Set(rootIds));
-      }
     } catch (error) {
       console.error("POP 그룹 로드 실패:", error);
       toast.error("그룹 목록 로드에 실패했습니다.");
@@ -934,7 +929,7 @@ export function PopCategoryTree({
   }
 
   return (
-    <div className="flex flex-col h-full">
+    <div className="flex flex-col h-full overflow-hidden">
       {/* 헤더 */}
       <div className="shrink-0 p-3 border-b flex items-center justify-between">
         <h3 className="text-sm font-medium">POP 카테고리</h3>
@@ -949,7 +944,7 @@ export function PopCategoryTree({
       </div>
 
       {/* 트리 영역 */}
-      <ScrollArea className="flex-1">
+      <ScrollArea className="flex-1 min-h-0">
         <div className="p-2">
           {treeData.length === 0 && ungroupedScreens.length === 0 ? (
             <div className="text-center text-sm text-muted-foreground py-8">
@@ -1009,16 +1004,42 @@ export function PopCategoryTree({
                       return acc;
                     }, {});
                     const companyKeys = Object.keys(grouped).sort();
-                    const hasMultipleCompanies = companyKeys.length > 1;
 
-                    return companyKeys.map((companyCode) => (
+                    const toggleCompanyCode = (code: string) => {
+                      setExpandedCompanyCodes((prev) => {
+                        const next = new Set(prev);
+                        if (next.has(code)) {
+                          next.delete(code);
+                        } else {
+                          next.add(code);
+                        }
+                        return next;
+                      });
+                    };
+
+                    return companyKeys.map((companyCode) => {
+                      const isExpanded = expandedCompanyCodes.has(companyCode);
+                      const label = companyCode === "*" ? "최고관리자" : companyCode;
+
+                      return (
                       <div key={`ungrouped-company-${companyCode}`}>
-                        {hasMultipleCompanies && (
-                          <div className="text-[10px] font-medium text-muted-foreground px-2 py-1 mt-1 bg-muted/50 rounded">
-                            {companyCode === "*" ? "최고관리자" : companyCode}
-                          </div>
-                        )}
-                        {grouped[companyCode].map((screen) => (
+                        <div
+                          className="flex items-center gap-1 px-2 py-1 mt-1 bg-muted/50 rounded cursor-pointer select-none hover:bg-muted transition-colors"
+                          onClick={() => toggleCompanyCode(companyCode)}
+                        >
+                          {isExpanded ? (
+                            <ChevronDown className="h-3 w-3 text-muted-foreground shrink-0" />
+                          ) : (
+                            <ChevronRight className="h-3 w-3 text-muted-foreground shrink-0" />
+                          )}
+                          <span className="text-[10px] font-medium text-muted-foreground">
+                            {label}
+                          </span>
+                          <Badge variant="outline" className="ml-auto h-4 text-[9px] px-1">
+                            {grouped[companyCode].length}
+                          </Badge>
+                        </div>
+                        {isExpanded && grouped[companyCode].map((screen) => (
                           <div
                             key={`ungrouped-${screen.screenId}`}
                             className={cn(
@@ -1027,7 +1048,7 @@ export function PopCategoryTree({
                                 ? "bg-primary/10 text-primary"
                                 : "hover:bg-muted",
                               "group",
-                              hasMultipleCompanies && "pl-4"
+                              "pl-4"
                             )}
                             onClick={() => onScreenSelect(screen)}
                             onDoubleClick={() => onScreenDesign(screen)}
@@ -1078,7 +1099,8 @@ export function PopCategoryTree({
                           </div>
                         ))}
                       </div>
-                    ));
+                      );
+                    });
                   })()}
                 </div>
               )}