feat: add xAI Grok adapters

tests/public-api.test.ts

@@ -1,5 +1,6 @@
 import { describe, expect, it } from 'vitest';
 import {
+  createGrokAdapters,
   createReplyDelay,
   createTypingDelay,
   generateSchedule,
@@ -38,7 +39,7 @@ describe('public API', () => {
     expect(fact.topics.map((topic) => topic.name)).toEqual(['Mina', 'quiet cafés']);
   });
 
-  it('exports schedule, conversation, and external special-date adapter contracts', () => {
+  it('exports schedule, conversation, Grok, and external special-date adapter contracts', () => {
     const specialDateProvider: SpecialDateProvider = {
       async listSpecialDates() {
         return [{ date: '2026-05-08', title: 'Parents Day' }];
@@ -47,6 +48,7 @@ describe('public API', () => {
 
     expect(typeof generateSchedule).toBe('function');
     expect(typeof replyToConversation).toBe('function');
+    expect(typeof createGrokAdapters).toBe('function');
     expect(specialDateProvider.listSpecialDates).toBeTypeOf('function');
   });
 });