feat(parent): add attention banner, export button, and grade detail

- Add parent-attention-banner for highlighting items needing attention

- Add parent-export-button for data export capability

- Add child-grade-detail component for detailed grade viewing

- Update existing child-card, child-detail-header, child-grade-summary, child-schedule-card

- Update parent-children-data-page and data-access

src/modules/parent/components/parent-children-data-page.tsx

@@ -15,6 +15,7 @@ export function ParentChildrenDataPage<T>({
   noRecordsDescription,
   items,
   renderItem,
+  headerExtra,
 }: {
   title: string
   description: string
@@ -23,6 +24,8 @@ export function ParentChildrenDataPage<T>({
   noRecordsDescription: string
   items: T[]
   renderItem: (item: T) => React.ReactNode
+  /** 渲染在标题与列表之间的额外内容（如预警横幅）。 */
+  headerExtra?: React.ReactNode
 }) {
   const hasItems = items.length > 0
 
@@ -33,6 +36,8 @@ export function ParentChildrenDataPage<T>({
         <p className="text-muted-foreground">{description}</p>
       </div>
 
+      {headerExtra}
+
       {!hasItems ? (
         <EmptyState
           title={noRecordsTitle}