feat: Refactor utility and component exports, update dependencies, and add Knip for unused code detection.

frontend/src/sidebar/SidebarContext.tsx

@@ -295,12 +295,3 @@ export const useSidebarContext = () => {
   }
   return context;
 };
-
-export const useSidebarControls = () => {
-  const { setCollapsed } = useSidebarContext();
-  const openSidebar = useCallback(() => setCollapsed(false), [setCollapsed]);
-  const closeSidebar = useCallback(() => setCollapsed(true), [setCollapsed]);
-  return { openSidebar, closeSidebar };
-};
-
-export default SidebarContext;

frontend/src/sidebar/components/SidebarFolderNode.tsx

@@ -20,7 +20,7 @@ export interface FolderTreeNode {
     expanded?: boolean;
 }
 
-export interface FolderNodeProps {
+interface FolderNodeProps {
     node: FolderTreeNode;
     depth: number;
     isSelected: boolean;