feat(KB-074): add quick task creation with QuickEntryBox and NewTaskModal

- Add QuickEntryBox component for inline quick task entry in columns
- Add NewTaskModal component with full-featured task creation UI
- Integrate quick create flow through Column → Board → App component hierarchy
- Add comprehensive tests for both new components and updated existing tests
- Add CSS styles for modal, form inputs, and quick entry UI
- Include changeset for @dustinbyrne/kb package release

packages/dashboard/app/components/Board.tsx

@@ -10,9 +10,7 @@ interface BoardProps {
   onMoveTask: (id: string, column: ColumnType) => Promise<Task>;
   onOpenDetail: (task: TaskDetail) => void;
   addToast: (message: string, type?: ToastType) => void;
-  isCreating: boolean;
-  onCancelCreate: () => void;
-  onCreateTask: (input: TaskCreateInput) => Promise<Task>;
+  onQuickCreate?: (description: string) => Promise<void>;
   onNewTask: () => void;
   autoMerge: boolean;
   onToggleAutoMerge: () => void;
@@ -25,7 +23,7 @@ interface BoardProps {
   onUnarchiveTask?: (id: string) => Promise<Task>;
 }
 
-export function Board({ tasks, maxConcurrent, onMoveTask, onOpenDetail, addToast, isCreating, onCancelCreate, onCreateTask, onNewTask, autoMerge, onToggleAutoMerge, globalPaused, onUpdateTask, onArchiveTask, onUnarchiveTask }: BoardProps) {
+export function Board({ tasks, maxConcurrent, onMoveTask, onOpenDetail, addToast, onQuickCreate, onNewTask, autoMerge, onToggleAutoMerge, globalPaused, onUpdateTask, onArchiveTask, onUnarchiveTask }: BoardProps) {
   const [archivedCollapsed, setArchivedCollapsed] = useState(true);
 
   return (
@@ -55,7 +53,7 @@ export function Board({ tasks, maxConcurrent, onMoveTask, onOpenDetail, addToast
           onUpdateTask={onUpdateTask}
           onArchiveTask={onArchiveTask}
           onUnarchiveTask={onUnarchiveTask}
-          {...(col === "triage" ? { isCreating, onCancelCreate, onCreateTask, onNewTask } : {})}
+          {...(col === "triage" ? { onQuickCreate, onNewTask } : {})}
           {...(col === "in-review" ? { autoMerge, onToggleAutoMerge } : {})}
           {...(col === "archived" ? { collapsed: archivedCollapsed, onToggleCollapse: () => setArchivedCollapsed(!archivedCollapsed) } : {})}
         />