re-reading a folder does not blank it

`loading` swaps the whole grid for a spinner. That is right when arriving somewhere new and wrong when
re-reading a folder already on screen — and every refresh went through the same path: after a paste,
after a delete, and now every time a window comes forward. On a folder of a hundred files that is a
flash and a lost scroll position, to replace information that was already correct.

The spinner is now for a folder that cannot yet be shown: nothing listed, or a different folder than
the one listed. Re-reading the same folder leaves what is there until better information arrives, so
the only visible change is whatever actually changed.

`shownPath` is what separates the two cases. From inside `refresh` they are identical — it is called
the same way by a navigation and by a refresh — and they need opposite treatment.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

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

@@ -247,6 +247,10 @@ export const useFileBrowserApp = (
   filesRef.current = files;
   const currentPathRef = useRef(currentPath);
   currentPathRef.current = currentPath;
+  // Read inside `refresh`, which is not re-created per render and would otherwise close over a
+  // stale list the first time it ran.
+  const entriesRef = useRef(entries);
+  entriesRef.current = entries;
   const visibleEntries = showHidden ? entries : entries.filter((e) => !e.name.startsWith('.'));
 
   const entryPath = (name: string) => (currentPath === '/' ? `/${name}` : `${currentPath}/${name}`);
@@ -254,8 +258,29 @@ export const useFileBrowserApp = (
 
   const firstListing = useRef(true);
 
+  /**
+   * The folder the entries currently on screen belong to.
+   *
+   * What separates "re-read this folder" from "go to a different one", which look identical from
+   * inside `refresh` and need opposite treatment — see below.
+   */
+  const shownPath = useRef<string | null>(null);
+
   const refresh = async () => {
-    setLoading(true);
+    /*
+      Blank the list only when there is nothing true to show.
+
+      `loading` swaps the whole grid for a spinner, which is right when arriving somewhere new and
+      wrong when re-reading a folder already on screen: every refresh — after a paste, after a delete,
+      and now every time the window comes forward — made the contents vanish and come back. On a
+      folder of a hundred files that is a flash and a lost scroll position, for information that was
+      already correct.
+
+      So the spinner is for a folder we cannot yet show: nothing listed, or a different folder than the
+      one listed. Re-reading the same folder leaves what is there until better information arrives, and
+      the only visible change is whatever actually changed.
+    */
+    if (entriesRef.current.length === 0 || shownPath.current !== currentPathRef.current) setLoading(true);
     try {
       const data = await filesRef.current.listDir(currentPathRef.current);
       if (data.reset) {
@@ -263,6 +288,7 @@ export const useFileBrowserApp = (
         return;
       }
       setEntries(data.entries);
+      shownPath.current = currentPathRef.current;
       if (data.rootDir) setRootDir(data.rootDir);
     } catch (err: any) {
       console.error('[FileBrowser] refresh error:', err);