feat: assistant role (#1588)

## Description

Introduces the ability for users with the **Assistant** role to prefill
fields on behalf of other signers. Assistants can fill in various field
types such as text, checkboxes, dates, and more, streamlining the
document preparation process before it reaches the final signers.

https://github.com/user-attachments/assets/c1321578-47ec-405b-a70a-7d9578385895

packages/ui/components/recipient/recipient-role-select.tsx

@@ -1,6 +1,6 @@
 'use client';
 
-import React, { forwardRef } from 'react';
+import { forwardRef } from 'react';
 
 import { Trans } from '@lingui/macro';
 import type { SelectProps } from '@radix-ui/react-select';
@@ -11,12 +11,15 @@ import { ROLE_ICONS } from '@documenso/ui/primitives/recipient-role-icons';
 import { Select, SelectContent, SelectItem, SelectTrigger } from '@documenso/ui/primitives/select';
 import { Tooltip, TooltipContent, TooltipTrigger } from '@documenso/ui/primitives/tooltip';
 
+import { cn } from '../../lib/utils';
+
 export type RecipientRoleSelectProps = SelectProps & {
   hideCCRecipients?: boolean;
+  isAssistantEnabled?: boolean;
 };
 
 export const RecipientRoleSelect = forwardRef<HTMLButtonElement, RecipientRoleSelectProps>(
-  ({ hideCCRecipients, ...props }, ref) => (
+  ({ hideCCRecipients, isAssistantEnabled = true, ...props }, ref) => (
     <Select {...props}>
       <SelectTrigger ref={ref} className="bg-background w-[50px] p-2">
         {/* eslint-disable-next-line @typescript-eslint/consistent-type-assertions */}
@@ -110,6 +113,42 @@ export const RecipientRoleSelect = forwardRef<HTMLButtonElement, RecipientRoleSe
             </div>
           </SelectItem>
         )}
+
+        <SelectItem
+          value={RecipientRole.ASSISTANT}
+          disabled={!isAssistantEnabled}
+          className={cn(
+            !isAssistantEnabled &&
+              'cursor-not-allowed opacity-50 data-[disabled]:pointer-events-auto',
+          )}
+        >
+          <div className="flex items-center">
+            <div className="flex w-[150px] items-center">
+              <span className="mr-2">{ROLE_ICONS[RecipientRole.ASSISTANT]}</span>
+              <Trans>Can prepare</Trans>
+            </div>
+            <Tooltip>
+              <TooltipTrigger>
+                <InfoIcon className="h-4 w-4" />
+              </TooltipTrigger>
+              <TooltipContent className="text-foreground z-9999 max-w-md p-4">
+                <p>
+                  {isAssistantEnabled ? (
+                    <Trans>
+                      The recipient can prepare the document for later signers by pre-filling
+                      suggest values.
+                    </Trans>
+                  ) : (
+                    <Trans>
+                      Assistant role is only available when the document is in sequential signing
+                      mode.
+                    </Trans>
+                  )}
+                </p>
+              </TooltipContent>
+            </Tooltip>
+          </div>
+        </SelectItem>
       </SelectContent>
     </Select>
   ),