feat: dictate next signer (#1719)

Adds next recipient dictation functionality to document signing flow,
allowing assistants and signers to update the next recipient's
information during the signing process.

## Related Issue

N/A

## Changes Made

- Added form handling for next recipient dictation in signing dialogs
- Implemented UI for updating next recipient information
- Added e2e tests covering dictation scenarios:
  - Regular signing with dictation enabled
  - Assistant role with dictation
  - Parallel signing flow
  - Disabled dictation state

## Testing Performed

- Added comprehensive e2e tests covering:
  - Sequential signing with dictation
  - Assistant role dictation
  - Parallel signing without dictation
  - Form validation and state management
- Tested on Chrome and Firefox
- Verified recipient state updates in database

packages/lib/server-only/recipient/get-next-pending-recipient.ts

@@ -0,0 +1,37 @@
+import { prisma } from '@documenso/prisma';
+
+export const getNextPendingRecipient = async ({
+  documentId,
+  currentRecipientId,
+}: {
+  documentId: number;
+  currentRecipientId: number;
+}) => {
+  const recipients = await prisma.recipient.findMany({
+    where: {
+      documentId,
+    },
+    orderBy: [
+      {
+        signingOrder: {
+          sort: 'asc',
+          nulls: 'last',
+        },
+      },
+      {
+        id: 'asc',
+      },
+    ],
+  });
+
+  const currentIndex = recipients.findIndex((r) => r.id === currentRecipientId);
+
+  if (currentIndex === -1 || currentIndex === recipients.length - 1) {
+    return null;
+  }
+
+  return {
+    ...recipients[currentIndex + 1],
+    token: '',
+  };
+};