feat: add pending signed pdf downloads for recipients

Recipients can download a PDF that contains the inserted fields while
the envelope is in the PENDING state.

The token file route accepts the `pending` version. The PDF contains
only the fields from recipients who signed and the fields of the
recipient who makes the request. This is the same set of fields that
the signing page shows to the recipient.

The signing page and the completion page show the download dialog for
pending envelopes. The dialog does not show the "Partial" button for
legacy envelopes.

apps/remix/app/routes/_recipient+/sign.$token+/complete.tsx

@@ -148,6 +148,13 @@ export default function CompletedSigningPage({ loaderData }: Route.ComponentProp
     );
   }
 
+  // The envelope may complete or get rejected while this page polls, so derive
+  // the download dialog status from the live signing status.
+  const envelopeStatus = match(signingStatus)
+    .with('COMPLETED', () => DocumentStatus.COMPLETED)
+    .with('REJECTED', () => DocumentStatus.REJECTED)
+    .otherwise(() => document.status);
+
   return (
     <>
       <RecipientBranding branding={branding} cspNonce={cspNonce} />
@@ -255,10 +262,11 @@ export default function CompletedSigningPage({ loaderData }: Route.ComponentProp
                 className="w-full max-w-none md:flex-1"
               />
 
-              {isDocumentCompleted(document) && (
+              {(isDocumentCompleted(envelopeStatus) || envelopeStatus === DocumentStatus.PENDING) && (
                 <EnvelopeDownloadDialog
                   envelopeId={document.envelopeId}
-                  envelopeStatus={document.status}
+                  envelopeStatus={envelopeStatus}
+                  isLegacy={document.internalVersion === 1}
                   envelopeItems={document.envelopeItems}
                   token={recipient?.token}
                   trigger={