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/handover/handover.spec.ts

@@ -0,0 +1,30 @@
+import { test, expect, expectUnchanged, AI_REPLY } from '@e2e'
+
+test.describe('human handover', () => {
+  test.use({ agentSettings: { transferToHuman: true } })
+
+  test('a customer asks for a person, the teammate\'s reply reaches them, and the AI stays out of it @smoke @handover', async ({ agent, widget, inbox, llm }) => {
+    await llm.script(agent, (s) => s
+      .when(/human|person/i).handOver('Let me connect you with a teammate.')
+      .otherwise().reply('Happy to help!'))
+
+    await widget.embed()
+    await widget.open()
+    await widget.send('I want to talk to a human')
+    await widget.shareContactDetails()
+
+    await inbox.goto()
+    await inbox.openConversationWith(widget.customer.name)
+    await inbox.takeOver()
+    await inbox.reply('Hi, this is Sam. How can I help?')
+    await expect(widget.lastAgentMessage()).toHaveText('Hi, this is Sam. How can I help?', AI_REPLY)
+
+    const modelCalls = (await llm.requests(agent)).length
+    await widget.send('My parcel never arrived')
+    await expect(inbox.lastCustomerMessage()).toContainText('My parcel never arrived')
+    // A person owns the chat now: the model is not asked, and no bot answer appears.
+    await expectUnchanged('model calls after takeover', async () => (await llm.requests(agent)).length)
+    expect((await llm.requests(agent))).toHaveLength(modelCalls)
+    await expect(widget.lastAgentMessage()).toHaveText('Hi, this is Sam. How can I help?')
+  })
+})