fix: prevent duplicate uploads and group asset commits

lib/upload-lock.ts

@@ -0,0 +1,16 @@
+const activeUploads = new Set<string>()
+
+function buildKey(folderName: string) {
+  return folderName.toLowerCase()
+}
+
+export function acquireUploadLock(folderName: string): boolean {
+  const key = buildKey(folderName)
+  if (activeUploads.has(key)) return false
+  activeUploads.add(key)
+  return true
+}
+
+export function releaseUploadLock(folderName: string) {
+  activeUploads.delete(buildKey(folderName))
+}