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/src/channels/sms.ts

@@ -0,0 +1,72 @@
+import { connectSms, routeToAgent } from '../api/channels'
+import { env } from '../env'
+import { FakeExternals } from '../fakes/externals'
+import { unique } from '../support/ids'
+import { step } from '../support/step'
+import { Chat, hmac, phoneNumber, postWebhook, samePhone, type ChannelConnector } from './chat'
+
+// SMS webhooks are per account and signed over the public webhook URL, which the
+// backend rebuilds from BACKEND_URL — the same URL the test posts to.
+
+interface TwilioSend { From: string; To: string; Body: string }
+interface PlivoSend { src: string; dst: string; text: string }
+
+/** Twilio: X-Twilio-Signature = base64(HMAC-SHA1(auth token, url + sorted key/value pairs)). */
+export const twilio: ChannelConnector = ({ api, request, agentId }) =>
+  step('Connect a Twilio number', async () => {
+    const authToken = unique('twilio-token')
+    const businessNumber = phoneNumber()
+    const accountSid = unique('AC')
+    const account = await connectSms(api, 'twilio', businessNumber, { account_sid: accountSid, auth_token: authToken })
+    await routeToAgent(api, account.id, agentId)
+    const externals = new FakeExternals(request)
+    const path = `/webhooks/sms/twilio/${account.id}`
+
+    return {
+      chatWith(customerName) {
+        const customerNumber = phoneNumber()
+        return new Chat('SMS (Twilio)', customerName, async (text) => {
+          const form = { From: customerNumber, To: businessNumber, Body: text, MessageSid: unique('SM') }
+          const signed = `${env.apiUrl}${path}` + Object.keys(form).sort().map((k) => k + form[k as keyof typeof form]).join('')
+          await postWebhook(request, path, { form }, { 'x-twilio-signature': hmac('sha1', authToken, signed).toString('base64') })
+        }, async () => (await externals.calls('twilio', 'Messages.json', { contains: accountSid }))
+          // Sent through this account (its SID in the path) from this number.
+          .filter((c) => c.status === 200 && c.path.includes(`/Accounts/${accountSid}/`))
+          .map((c) => c.body as TwilioSend)
+          .filter((b) => samePhone(b.To, customerNumber) && samePhone(b.From, businessNumber))
+          .map((b) => b.Body))
+      },
+    }
+  })
+
+/** Plivo: X-Plivo-Signature-V3 = base64(HMAC-SHA256(auth token, url + nonce)). */
+export const plivo: ChannelConnector = ({ api, request, agentId }) =>
+  step('Connect a Plivo number', async () => {
+    const authToken = unique('plivo-token')
+    const businessNumber = phoneNumber()
+    const authId = unique('MA')
+    const account = await connectSms(api, 'plivo', businessNumber, { auth_id: authId, auth_token: authToken })
+    await routeToAgent(api, account.id, agentId)
+    const externals = new FakeExternals(request)
+    const path = `/webhooks/sms/plivo/${account.id}`
+
+    return {
+      chatWith(customerName) {
+        // Plivo sends numbers without the leading +.
+        const customerNumber = phoneNumber().slice(1)
+        return new Chat('SMS (Plivo)', customerName, async (text) => {
+          const nonce = unique('nonce')
+          await postWebhook(request, path, {
+            form: { From: customerNumber, To: businessNumber.slice(1), Text: text, MessageUUID: unique('uuid') },
+          }, {
+            'x-plivo-signature-v3': hmac('sha256', authToken, `${env.apiUrl}${path}${nonce}`).toString('base64'),
+            'x-plivo-signature-v3-nonce': nonce,
+          })
+        }, async () => (await externals.calls('plivo', 'Message', { contains: authId }))
+          .filter((c) => c.status === 200 && c.path.includes(`/Account/${authId}/`))
+          .map((c) => c.body as PlivoSend)
+          .filter((b) => samePhone(b.dst, customerNumber) && samePhone(b.src, businessNumber))
+          .map((b) => b.text))
+      },
+    }
+  })