fix: handle Telegram network errors gracefully to prevent gateway crashes

- Expand recoverable error codes (ECONNABORTED, ERR_NETWORK)
- Add message patterns for 'typeerror: fetch failed' and 'undici' errors
- Add isNetworkRelatedError() helper for broad network failure detection
- Retry on all network-related errors instead of crashing gateway
- Remove unnecessary 'void' from fire-and-forget patterns
- Add tests for new error patterns

Fixes #3005

src/telegram/network-errors.ts

@@ -15,6 +15,8 @@ const RECOVERABLE_ERROR_CODES = new Set([
   "UND_ERR_BODY_TIMEOUT",
   "UND_ERR_SOCKET",
   "UND_ERR_ABORTED",
+  "ECONNABORTED",
+  "ERR_NETWORK",
 ]);
 
 const RECOVERABLE_ERROR_NAMES = new Set([
@@ -27,6 +29,8 @@ const RECOVERABLE_ERROR_NAMES = new Set([
 
 const RECOVERABLE_MESSAGE_SNIPPETS = [
   "fetch failed",
+  "typeerror: fetch failed",
+  "undici",
   "network error",
   "network request",
   "client network socket disconnected",