fix(telegram): lower webhook callback timeout to 5s

#16763 added `onTimeout: "return"` with `timeoutMilliseconds: 10_000`
(grammY default). In practice, Telegram's webhook servers abort the
read well before 10s when handler latency is LLM-bound: `getWebhookInfo`
reports `last_error_message: "Read timeout expired"` and pending updates
pile up, cascading into multi-minute reply lag.

Reproducible A/B on identical infra (same region, same bot token):
- Minimal Python echo bot: 5 back-to-back webhook RTTs 341-642ms, clean.
- OpenClaw current main: intermittent Read timeout expired, 1-5 min lag.

The handler still runs to completion; only the Telegram-facing ack is
sooner. grammY's deployment guide suggests 5s for long-running handlers.

No new config surface; minimal one-line change to the existing constant
and its test assertion. If a configurable timeout is wanted, that can be
a follow-up (see stale #7754).

extensions/telegram/src/webhook.test.ts

@@ -455,7 +455,7 @@ describe("startTelegramWebhook", () => {
           {
             secretToken: TELEGRAM_SECRET,
             onTimeout: "return",
-            timeoutMilliseconds: 10_000,
+            timeoutMilliseconds: 5_000,
           },
         );
         expect(runtimeLog).toHaveBeenCalledWith(

extensions/telegram/src/webhook.ts

@@ -28,7 +28,7 @@ import { createTelegramBot } from "./bot.js";
 
 const TELEGRAM_WEBHOOK_MAX_BODY_BYTES = 1024 * 1024;
 const TELEGRAM_WEBHOOK_BODY_TIMEOUT_MS = 30_000;
-const TELEGRAM_WEBHOOK_CALLBACK_TIMEOUT_MS = 10_000;
+const TELEGRAM_WEBHOOK_CALLBACK_TIMEOUT_MS = 5_000;
 const InputFileCtor: typeof grammy.InputFile =
   typeof grammy.InputFile === "function"
     ? grammy.InputFile