feat: 리스트 헤더 스타일 개선 - 그라데이션 배경, 굵은 테두리, 호버 효과 추가

frontend/components/screen/InteractiveDataTable.tsx

@@ -1954,7 +1954,7 @@ export const InteractiveDataTable: React.FC<InteractiveDataTableProps> = ({
             <>
               <div className="overflow-hidden rounded-lg border border-gray-200/60 bg-white shadow-sm">
                 <Table style={{ tableLayout: 'fixed' }}>
-                  <TableHeader>
+                  <TableHeader className="bg-gradient-to-b from-muted/50 to-muted border-b-2 border-primary/20">
                     <TableRow>
                       {/* 체크박스 컬럼 (삭제 기능이 활성화된 경우) */}
                       {component.enableDelete && (
@@ -1975,7 +1975,7 @@ export const InteractiveDataTable: React.FC<InteractiveDataTableProps> = ({
                           <TableHead
                             key={column.id}
                             ref={(el) => (columnRefs.current[column.id] = el)}
-                            className="relative bg-gradient-to-r from-gray-50 to-slate-50 px-4 font-semibold text-gray-700 select-none text-center"
+                            className="relative px-4 font-bold text-foreground/90 select-none text-center hover:bg-muted/70 transition-colors"
                             style={{ 
                               width: columnWidth ? `${columnWidth}px` : undefined,
                               userSelect: 'none'