fix(telegram): handle network errors gracefully

- Add bot.catch() to prevent unhandled rejections from middleware
- Add isRecoverableNetworkError() to retry on transient failures
- Add maxRetryTime and exponential backoff to grammY runner
- Global unhandled rejection handler now logs recoverable errors
  instead of crashing (fetch failures, timeouts, connection resets)

Fixes crash loop when Telegram API is temporarily unreachable.

src/telegram/bot.ts

@@ -138,6 +138,12 @@ export function createTelegramBot(opts: TelegramBotOptions) {
   bot.api.config.use(apiThrottler());
   bot.use(sequentialize(getTelegramSequentialKey));
 
+  // Catch all errors from bot middleware to prevent unhandled rejections
+  bot.catch((err) => {
+    const message = err instanceof Error ? err.message : String(err);
+    runtime.error?.(danger(`telegram bot error: ${message}`));
+  });
+
   const recentUpdates = createTelegramUpdateDedupe();
   let lastUpdateId =
     typeof opts.updateOffset?.lastUpdateId === "number" ? opts.updateOffset.lastUpdateId : null;