add header rescan button to apply officer-items changes without restart

New POST /api/rescan re-runs the boot item setup (ensureItemDirs +
ensureToolLoader) and returns live item counts; the header button calls it
and invalidates the item query caches so the UI refetches from disk.

Also fix ensure-tool-loader to write into OFFICER_ITEMS_DIR/extensions (the
runtime read path) instead of the now-unread DATA_PATH/extensions.

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

src/apps/officer-web/Screens/Dashboard/Layout/Header/Header.tsx

@@ -6,6 +6,7 @@ import { Sheet, SheetContent, SheetHeader, SheetTitle } from '@/components/ui/sh
 import type { DockItem } from '../Dock';
 import { useIsTouch } from '../useIsTouch';
 import { UserMenu } from './UserMenu';
+import { RescanButton } from '../Rescan/RescanButton';
 // import { BugReportButton } from '../BugReport/BugReportButton';
 
 type HeaderProps = {
@@ -52,6 +53,7 @@ export function Header({ dockItems }: HeaderProps) {
           */}
           {/* Bug Report — hidden */}
           {/* <BugReportButton /> */}
+          <RescanButton />
           <UserMenu />
         </div>
       </div>