Preserve Telegram onboarding fallback errors

tests/hermes_cli/test_web_server.py

@@ -1182,6 +1182,26 @@ class TestWebServerEndpoints:
         assert kwargs["headers"]["Content-Type"] == "application/json"
         assert kwargs["headers"]["User-Agent"].startswith("HermesDashboard/")
 
+    def test_telegram_onboarding_worker_request_maps_unexpected_errors(
+        self, monkeypatch
+    ):
+        import hermes_cli.web_server as ws
+
+        monkeypatch.setenv("TELEGRAM_ONBOARDING_URL", "not a valid url")
+
+        with pytest.raises(ws.HTTPException) as exc:
+            ws._telegram_onboarding_request_sync(
+                "POST",
+                "/v1/telegram/pairings",
+                body={"bot_name": "Hermes Agent"},
+            )
+
+        assert exc.value.status_code == 502
+        assert (
+            exc.value.detail
+            == "Telegram setup service is unavailable. Try again shortly."
+        )
+
     def test_telegram_onboarding_start_strips_poll_token(self, monkeypatch):
         import hermes_cli.web_server as ws