feat(KB-048): add collapsible list sections to dashboard

- Add section expansion state management with localStorage persistence
- Update section headers with chevron toggle controls
- Implement conditional task row rendering based on section state
- Add Expand All / Collapse All toolbar controls
- Add CSS styles for chevron rotation animation and section headers
- Add comprehensive tests for collapsible section behavior

packages/dashboard/app/components/Board.tsx

@@ -16,9 +16,13 @@ interface BoardProps {
   autoMerge: boolean;
   onToggleAutoMerge: () => void;
   globalPaused?: boolean;
+  onUpdateTask?: (
+    id: string,
+    updates: { title?: string; description?: string; dependencies?: string[] }
+  ) => Promise<Task>;
 }
 
-export function Board({ tasks, maxConcurrent, onMoveTask, onOpenDetail, addToast, isCreating, onCancelCreate, onCreateTask, onNewTask, autoMerge, onToggleAutoMerge, globalPaused }: BoardProps) {
+export function Board({ tasks, maxConcurrent, onMoveTask, onOpenDetail, addToast, isCreating, onCancelCreate, onCreateTask, onNewTask, autoMerge, onToggleAutoMerge, globalPaused, onUpdateTask }: BoardProps) {
   return (
     <main className="board" id="board">
       {COLUMNS.map((col) => (
@@ -43,6 +47,7 @@ export function Board({ tasks, maxConcurrent, onMoveTask, onOpenDetail, addToast
           onOpenDetail={onOpenDetail}
           addToast={addToast}
           globalPaused={globalPaused}
+          onUpdateTask={onUpdateTask}
           {...(col === "triage" ? { isCreating, onCancelCreate, onCreateTask, onNewTask } : {})}
           {...(col === "in-review" ? { autoMerge, onToggleAutoMerge } : {})}
         />