docs: 交付文档、维护指引与端到端回归

补齐 README、开发计划、维护交接与 E2E 用例，执行最终验收。

e2e/specs/channels/reply-buttons.spec.ts

@@ -0,0 +1,21 @@
+import { test, expect, channelsWithButtons, AI_REPLY } from '@e2e'
+
+test.describe('reply buttons', () => {
+  test.use({ agentSettings: { channelQuickReplies: true } })
+
+  for (const [name, connect] of Object.entries(channelsWithButtons)) {
+    test(`the AI offers buttons on ${name} and a tap gets the next answer @channels`, async ({ agent, llm, adminApi, request }) => {
+      await llm.script(agent, (s) => s
+        .when(/track my order/i).reply('Your order ships tomorrow.')
+        .otherwise().reply('What can I help you with?', { quick_replies: ['Track my order', 'Returns'] }))
+
+      const chat = (await connect({ api: adminApi, request, agentId: agent.id })).chatWith('Tess')
+      await chat.send('Hi')
+      await expect.poll(() => chat.buttons(), AI_REPLY).toEqual(['Track my order', 'Returns'])
+
+      await chat.tap('Track my order')
+      await expect.poll(async () => (await chat.replies()).at(-1), AI_REPLY).toContain('Your order ships tomorrow.')
+      expect(await chat.replies()).toHaveLength(2)
+    })
+  }
+})