file browser: type-ahead jump-to-item, flips to filter on longer bursts

Replaces the old "any key focuses the search box" with classic file-manager
type-ahead in FileGrid: keys within 1s accumulate into a burst. 1–2 chars select
and scroll to the first item (folder or file, in sort order) whose name starts
with the burst; the 3rd char flips it into the search filter (dumps the typed
text into the box and hands off focus, cursor at end). Idle >1s resets the burst.
Removed the single-key focus-search branch from useFileBrowserApp.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/workspaces/officerdev/src/apps/FileBrowser/FileBrowserApp/components/FileGrid.tsx

@@ -17,6 +17,10 @@ const LIST_ROW_HEIGHT = 42;
 const GRID_ROW_HEIGHT = 130;
 const GRID_GAP = 12;
 const HEADER_HEIGHT = 36;
+// Type-ahead: keys pressed within this window accumulate into one burst. 1–2 chars jump to the first
+// matching item; the 3rd char flips the burst into the search filter. Idle past the window resets it.
+const TYPEAHEAD_RESET_MS = 1000;
+const TYPEAHEAD_FILTER_AT = 3;
 
 const useColumnCount = (scrollRef: React.RefObject<HTMLDivElement | null>) => {
   const [cols, setCols] = useState(4);
@@ -67,6 +71,8 @@ export const FileGrid = ({ fileBrowserManager }: FileGridProps) => {
     handleRunTask,
     handleCreateDashboard,
     fileScrollRef: scrollRef,
+    setSearchQuery,
+    searchInputRef,
   } = fileBrowserManager;
   const { defaultSort } = fileBrowserManager;
   const lastClickedIdx = useRef<number>(-1);
@@ -152,6 +158,65 @@ export const FileGrid = ({ fileBrowserManager }: FileGridProps) => {
     scrollMargin: HEADER_HEIGHT,
   });
 
+  // Refs hold the latest values so the once-registered keydown listener always reads fresh state.
+  const sortedRef = useRef(sorted);
+  sortedRef.current = sorted;
+  const colsRef = useRef(cols);
+  colsRef.current = cols;
+  const viewModeRef = useRef(viewMode);
+  viewModeRef.current = viewMode;
+  const virtualizerRef = useRef(virtualizer);
+  virtualizerRef.current = virtualizer;
+
+  // Type-ahead (see constants above): jump-to-item on a short burst, flip to the filter on the 3rd key.
+  useEffect(() => {
+    let buffer = '';
+    let timer: ReturnType<typeof setTimeout> | undefined;
+    const reset = () => {
+      buffer = '';
+      if (timer) clearTimeout(timer);
+      timer = undefined;
+    };
+    const onKey = (ev: KeyboardEvent) => {
+      const t = ev.target as HTMLElement;
+      if (t.tagName === 'INPUT' || t.tagName === 'TEXTAREA' || t.closest('.monaco-editor')) return;
+      if (ev.ctrlKey || ev.metaKey || ev.altKey || ev.key.length !== 1) return; // printable, unmodified only
+
+      ev.preventDefault();
+      if (timer) clearTimeout(timer);
+      buffer += ev.key;
+      timer = setTimeout(reset, TYPEAHEAD_RESET_MS);
+      const typed = buffer;
+
+      // Kept typing → treat it as a filter: dump the burst into the search box and hand off focus.
+      if (typed.length >= TYPEAHEAD_FILTER_AT) {
+        reset();
+        setSearchQuery(typed);
+        requestAnimationFrame(() => {
+          const el = searchInputRef.current;
+          if (!el) return;
+          el.focus();
+          el.setSelectionRange(el.value.length, el.value.length); // cursor at the end, keep typing
+        });
+        return;
+      }
+
+      // Short burst → jump: select + scroll to the first item (folder or file) whose name starts with it.
+      const prefix = typed.toLowerCase();
+      const list = sortedRef.current;
+      const idx = list.findIndex((e) => e.name.toLowerCase().startsWith(prefix));
+      if (idx < 0) return;
+      setSelected(new Set([list[idx]!.name]));
+      const row = viewModeRef.current === 'list' ? idx : Math.floor(idx / Math.max(1, colsRef.current));
+      virtualizerRef.current.scrollToIndex(row, { align: 'auto' });
+    };
+    window.addEventListener('keydown', onKey);
+    return () => {
+      window.removeEventListener('keydown', onKey);
+      if (timer) clearTimeout(timer);
+    };
+  }, [setSearchQuery, searchInputRef, setSelected]);
+
   if (entries.length === 0) {
     return <div className="flex items-center justify-center py-20 text-duck-dark/40 text-sm">This folder is empty</div>;
   }

src/workspaces/officerdev/src/apps/FileBrowser/FileBrowserApp/useFileBrowserApp.ts

@@ -237,9 +237,7 @@ export const useFileBrowserApp = (
         return;
       }
 
-      if (ev.key.length === 1 && !ev.ctrlKey && !ev.metaKey && !ev.altKey) {
-        searchInputRef.current?.focus();
-      }
+      // (Printable keys are handled by FileGrid's type-ahead: jump-to-item, or flip to the filter.)
     };
 
     window.addEventListener('keydown', handler);