fix(files): attach the download anchor and handle a finalize rejection

A detached anchor's click() works in current browsers, but every other download
helper in the app attaches first, and a silent no-op on this path would look
exactly like a download that never started. Not worth the ambiguity for two DOM
operations.

archive.finalize() was fired with void, so a failure after the response had
started became an unhandled rejection on top of the stream error event that
already fails the response. It is caught and logged now.

Author: waleedlatif1

apps/sim/app/api/workspaces/[id]/files/download/route.ts

@@ -238,7 +238,11 @@ export const GET = withRouteHandler(
         const rendered = renderedDocuments.get(file.id)
         archive.append(rendered ?? lazyWorkspaceFileStream(file), { name: entryPaths[index] })
       })
-      void archive.finalize()
+      archive.finalize().catch((error) => {
+        // The archive's `error` event already fails the response stream; this keeps the
+        // same failure from also surfacing as an unhandled rejection.
+        logger.error('Failed to finalize workspace file archive', { error })
+      })
 
       recordAudit({
         workspaceId,

apps/sim/lib/uploads/client/download.ts

@@ -7,7 +7,12 @@ export function saveBlob(blob: Blob, fileName: string): void {
   const anchor = document.createElement('a')
   anchor.href = objectUrl
   anchor.download = fileName
+  // Attached before clicking: a detached anchor works in current browsers, but every
+  // other download helper in the app attaches, and a silent no-op here would look
+  // exactly like a download that never started.
+  document.body.appendChild(anchor)
   anchor.click()
+  document.body.removeChild(anchor)
   // Deferred: revoking synchronously after click() can race the download starting.
   setTimeout(() => URL.revokeObjectURL(objectUrl), 0)
 }