feat(doclist): add mobile sidebar close handler to FinderWindow and DocumentList

Introduce onRequestSidebarClose prop to FinderWindow and implement its
usage in DocumentList to enable closing the sidebar on mobile via
backdrop tap or Esc key. Enhances mobile usability by allowing users to
dismiss the sidebar more intuitively.

src/components/doclist/DocumentList.tsx

@@ -544,6 +544,9 @@ function DocumentListInner({ brand, appActions }: DocumentListInnerProps) {
         />
       }
       sidebarOpen={effectiveSidebarOpen}
+      onRequestSidebarClose={() => {
+        if (isNarrow) setMobileSidebarOpen(false);
+      }}
     >
       {!isLoading && showHint && allDocuments.length > 1 && (
         <div className="px-3 pt-3 shrink-0 bg-background">

src/components/doclist/window/FinderWindow.tsx

@@ -10,6 +10,8 @@ interface FinderWindowProps {
   children: ReactNode;
   /** Controlled sidebar open/closed state (drives mobile drawer + desktop collapse). */
   sidebarOpen: boolean;
+  /** Handles close requests from mobile drawer interactions (backdrop tap, Esc). */
+  onRequestSidebarClose?: () => void;
 }
 
 const NARROW_QUERY = '(max-width: 767px)';
@@ -37,6 +39,7 @@ export function FinderWindow({
   statusBar,
   children,
   sidebarOpen,
+  onRequestSidebarClose,
 }: FinderWindowProps) {
   const isNarrow = useIsNarrow();
 
@@ -59,7 +62,7 @@ export function FinderWindow({
       {/* Mobile drawer */}
       <Transition show={isNarrow && sidebarOpen} as={Fragment}>
         <Dialog
-          onClose={() => undefined}
+          onClose={onRequestSidebarClose ?? (() => undefined)}
           className="relative z-40 md:hidden"
         >
           <TransitionChild