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/knowledge/knowledge-lifecycle.spec.ts

@@ -0,0 +1,41 @@
+import { test, expect, addKnowledgeText, deleteKnowledge, unique, AI_REPLY, type TestAgent, type FakeLlm, type ChatWidget } from '@e2e'
+
+// What the model is shown is what the knowledge base holds for *this* agent, now.
+
+async function askAboutReturns(llm: FakeLlm, agent: TestAgent, widget: ChatWidget): Promise<string> {
+  await llm.script(agent, (s) => s
+    .when(/return/i).callTool('search_knowledge_base', { query: 'returns policy' })
+    .thenReply('Let me check our policy.')
+    .otherwise().reply('Happy to help!'))
+  await widget.embed()
+  await widget.open()
+  await widget.send('What is your returns policy?')
+  await expect(widget.lastAgentMessage()).toHaveText('Let me check our policy.', AI_REPLY)
+  return (await llm.requests(agent)).flatMap((r) => r.toolResults).join('\n')
+}
+
+test.describe('knowledge base lifecycle', () => {
+  test('deleted knowledge is no longer what the AI is shown @knowledge', async ({ agent, widget, llm, adminApi, org, makeWidget }) => {
+    const code = unique('RET')
+    const id = await addKnowledgeText(adminApi, {
+      orgId: org.orgId, agentId: agent.id, title: `Returns policy ${code}`,
+      content: `Returns policy: items can be returned within 45 days. Reference ${code}.`,
+    })
+    expect(await askAboutReturns(llm, agent, widget)).toContain(code)
+
+    await deleteKnowledge(adminApi, id)
+    const freshVisitor = await makeWidget(agent.id)
+    expect(await askAboutReturns(llm, agent, freshVisitor)).not.toContain(code)
+  })
+
+  test('one agent\'s knowledge never reaches another agent\'s answers @knowledge', async ({ agent, widget, llm, adminApi, org, makeAgent }) => {
+    const other = await makeAgent()
+    const secret = unique('INTERNAL')
+    await addKnowledgeText(adminApi, {
+      orgId: org.orgId, agentId: other.id, title: `Staff returns rules ${secret}`,
+      content: `Staff-only returns rules: discount code ${secret} for internal returns.`,
+    })
+    // `agent` searches the same org's knowledge base, for the same words.
+    expect(await askAboutReturns(llm, agent, widget)).not.toContain(secret)
+  })
+})