feat(v2/telegram): send pairing-success confirmation to paired chat

After a Telegram pair-code is successfully consumed, send a one-shot
"Pairing success! I'm spinning up the agent now, you'll get a message
from them shortly." reply to the same chat so the user knows the code
was accepted before the agent's own welcome DM arrives.

Best-effort: any sendMessage failure is logged but not rethrown, so a
Telegram outage can't undo a successful pairing or trigger the
interceptor's fail-open path.

Also includes a no-op prettier reformat in chat-sdk-bridge.ts that the
husky hook missed in the previous commit.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/channels/chat-sdk-bridge.ts

@@ -124,9 +124,7 @@ export function createChatSdkBridge(config: ChatSdkBridgeConfig): ChannelAdapter
     // Project chat-sdk's nested author into the flat sender fields the router
     // expects (see src/router.ts extractAndUpsertUser). Native adapters already
     // populate these directly; this brings chat-sdk adapters in line.
-    const author = serialized.author as
+    const author = serialized.author as { userId?: string; fullName?: string; userName?: string } | undefined;
-      | { userId?: string; fullName?: string; userName?: string }
-      | undefined;
     if (author) {
       const name = author.fullName ?? author.userName;
       serialized.senderId = author.userId;

src/channels/telegram.ts

@@ -85,9 +85,35 @@ function readInboundFields(message: InboundMessage): InboundFields {
  * the user to owner if the instance has no owner yet, and short-circuits.
  * On miss: forwards to the host.
  */
+/**
+ * Send a one-shot confirmation back to the paired chat. Best-effort — failures
+ * are logged but never propagated, so a Telegram outage can't undo a successful
+ * pairing or trigger the interceptor's fail-open path.
+ */
+async function sendPairingConfirmation(token: string, platformId: string): Promise<void> {
+  const chatId = platformId.split(':').slice(1).join(':');
+  if (!chatId) return;
+  try {
+    const res = await fetch(`https://api.telegram.org/bot${token}/sendMessage`, {
+      method: 'POST',
+      headers: { 'content-type': 'application/json' },
+      body: JSON.stringify({
+        chat_id: chatId,
+        text: "Pairing success! I'm spinning up the agent now, you'll get a message from them shortly.",
+      }),
+    });
+    if (!res.ok) {
+      log.warn('Telegram pairing confirmation non-OK', { status: res.status });
+    }
+  } catch (err) {
+    log.warn('Telegram pairing confirmation failed', { err });
+  }
+}
+
 function createPairingInterceptor(
   botUsernamePromise: Promise<string | null>,
   hostOnInbound: ChannelSetup['onInbound'],
+  token: string,
 ): ChannelSetup['onInbound'] {
   return (platformId, threadId, message) => {
     void (async () => {
@@ -159,6 +185,8 @@ function createPairingInterceptor(
         promotedToOwner,
         intent: consumed.intent,
       });
+
+      await sendPairingConfirmation(token, platformId);
     })().catch((err) => {
       log.error('Telegram pairing interceptor error', { err });
       // Fail open: pass through so a pairing bug doesn't break normal traffic.
@@ -191,7 +219,7 @@ registerChannelAdapter('telegram', {
       async setup(hostConfig: ChannelSetup) {
         const intercepted: ChannelSetup = {
           ...hostConfig,
-          onInbound: createPairingInterceptor(botUsernamePromise, hostConfig.onInbound),
+          onInbound: createPairingInterceptor(botUsernamePromise, hostConfig.onInbound, token),
         };
         return withRetry(() => bridge.setup(intercepted), 'bridge.setup');
       },