0.37.4: fix folder upload doing nothing (set webkitdirectory reliably)

"Upload folder" silently did nothing: the directory-selection attribute
was set on the hidden <input> via a JSX spread
({...{webkitdirectory:"", directory:""}}), which React doesn't reliably
apply to the DOM — and if isAdmin resolves after first render, a one-shot
effect would miss the input mounting entirely. Without the attribute the
picker is a plain file picker where no folder can be selected, so the user
picks nothing and nothing happens.

- Set webkitdirectory/directory/mozdirectory imperatively through a
  callback ref, which runs whenever the input mounts. folderInput is now a
  MutableRefObject so the callback can populate it.
- Folder upload now shows the progress bar immediately on start (small
  files can finish before the browser emits any upload-progress event, so
  don't wait for the first one to render feedback).

Frontend-only; all 3 images rebuilt+pushed 0.37.4.

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

backend/version.py

@@ -1,3 +1,3 @@
 """Single source of truth for the StackPilot release version."""
 
-APP_VERSION = "0.37.3"
+APP_VERSION = "0.37.4"

frontend/package.json

@@ -1,7 +1,7 @@
 {
   "name": "stackpilot-frontend",
   "private": true,
-  "version": "0.37.3",
+  "version": "0.37.4",
   "type": "module",
   "scripts": {
     "dev": "vite",

frontend/src/pages/Files.tsx

@@ -1,4 +1,4 @@
-import { useEffect, useRef, useState } from "react";
+import { useCallback, useEffect, useRef, useState } from "react";
 import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
 import {
   Folder,
@@ -92,7 +92,22 @@ export function Files() {
     detail?: string;
   } | null>(null);
   const fileInput = useRef<HTMLInputElement>(null);
-  const folderInput = useRef<HTMLInputElement>(null);
+  const folderInput = useRef<HTMLInputElement | null>(null);
+
+  // Callback ref for the folder <input>. Enables directory selection
+  // imperatively: setting `webkitdirectory` via JSX is unreliable (React
+  // doesn't reliably apply the non-standard attribute), and without it the
+  // picker is a plain file picker where no folder can be chosen — so "Upload
+  // folder" silently does nothing. A callback ref also runs whenever the input
+  // mounts (e.g. once `isAdmin` resolves), which a one-shot effect would miss.
+  const folderInputRef = useCallback((el: HTMLInputElement | null) => {
+    folderInput.current = el;
+    if (el) {
+      el.setAttribute("webkitdirectory", "");
+      el.setAttribute("directory", "");
+      el.setAttribute("mozdirectory", "");
+    }
+  }, []);
 
   const agents = useQuery({
     queryKey: ["agents"],
@@ -155,6 +170,14 @@ export function Files() {
       let ok = 0;
       let failed = 0;
       let doneBytes = 0; // bytes of fully-completed files
+      // Show the bar immediately — small files may finish before the browser
+      // emits any upload-progress event, so don't wait for the first one.
+      setProgress({
+        label: files[0]?.name ?? "",
+        pct: 0,
+        kind: "upload",
+        detail: `0 / ${total} files · ${formatBytes(0)} / ${formatBytes(totalBytes)}`,
+      });
       for (let i = 0; i < files.length; i++) {
         const f = files[i];
         const rel = (f as File & { webkitRelativePath?: string }).webkitRelativePath || f.name;
@@ -315,13 +338,12 @@ export function Files() {
                   if (f) upload.mutate(f);
                 }}
               />
+              {/* webkitdirectory is set imperatively via the callback ref. */}
               <input
-                ref={folderInput}
+                ref={folderInputRef}
                 type="file"
                 className="hidden"
                 multiple
-                // webkitdirectory/directory are non-standard but widely supported.
-                {...({ webkitdirectory: "", directory: "" } as Record<string, string>)}
                 onChange={(e) => {
                   const files = Array.from(e.target.files ?? []);
                   if (files.length) uploadFolder.mutate(files);