feat: add field and recipient endpoints

packages/lib/server-only/recipient/get-recipient-by-email.ts

@@ -0,0 +1,21 @@
+import { prisma } from '@documenso/prisma';
+
+export type GetRecipientByEmailOptions = {
+  documentId: number;
+  email: string;
+};
+
+export const getRecipientByEmail = async ({ documentId, email }: GetRecipientByEmailOptions) => {
+  const recipient = await prisma.recipient.findFirst({
+    where: {
+      documentId,
+      email: email.toLowerCase(),
+    },
+  });
+
+  if (!recipient) {
+    throw new Error('Recipient not found');
+  }
+
+  return recipient;
+};