fix(files): guard the archive download against concurrent clicks

Navigating to the route meant a second click just re-navigated. Fetching the
archive instead means each click starts another download that holds the whole
zip in tab memory, and the Download button gave no sign anything was happening.

The button now reflects the in-flight download alongside the existing move and
delete states. The ref guard is there as well as the state because two clicks in
the same tick would both pass a state check.

Author: waleedlatif1

apps/sim/app/workspace/[workspaceId]/files/files.tsx

@@ -1072,13 +1072,24 @@ export function Files() {
     setShowDeleteConfirm(true)
   }, [selectedFileIds, selectedFolderIds, files, folders])
 
+  const [isDownloadingArchive, setIsDownloadingArchive] = useState(false)
+  // Ref as well as state: two clicks in the same tick would both pass a state check,
+  // and each concurrent archive holds the whole zip in tab memory.
+  const archiveDownloadInFlightRef = useRef(false)
+
   const downloadArchive = useCallback(
     async (selection: { fileIds?: string[]; folderIds?: string[] }) => {
+      if (archiveDownloadInFlightRef.current) return
+      archiveDownloadInFlightRef.current = true
+      setIsDownloadingArchive(true)
       try {
         await triggerArchiveDownload({ workspaceId, ...selection })
       } catch (err) {
         logger.error('Failed to download selection:', err)
         toast.error(getErrorMessage(err, 'Failed to download the selected files'))
+      } finally {
+        archiveDownloadInFlightRef.current = false
+        setIsDownloadingArchive(false)
       }
     },
     [workspaceId]
@@ -1991,7 +2002,9 @@ export function Files() {
                 onMove={canEdit ? handleContextMenuMove : undefined}
                 moveOptions={canEdit ? contextMenuMoveOptions : undefined}
                 onDelete={canEdit ? handleBulkDelete : undefined}
-                isLoading={bulkArchiveItems.isPending || moveItems.isPending}
+                isLoading={
+                  bulkArchiveItems.isPending || moveItems.isPending || isDownloadingArchive
+                }
               />
               {isDraggingOver ? (
                 <div className='pointer-events-none absolute inset-0 z-[var(--z-dropdown)] flex flex-col items-center justify-center gap-2 border border-[var(--brand-secondary)] border-dashed bg-[var(--surface-4)] transition-colors'>