test(gateway): the NS-609 mixed boot is degraded, not running

CI: `test_token_lock_plus_retryable_peer_stays_alive` pinned `running` for a
boot whose Telegram adapter is parked fatal while Discord retries. That is a
serving gateway with a parked platform, which this stack stamps `degraded`
for its whole life; the assertion was the stale half of the contract.

All 67 test files that touch gateway_state / the status derivations: green.

tests/gateway/test_runner_startup_failures.py

@@ -570,7 +570,8 @@ async def test_token_lock_plus_retryable_peer_stays_alive(monkeypatch, tmp_path)
         assert runner.exit_code is None
         assert set(runner._failed_platforms) == {Platform.DISCORD}
         state = read_runtime_status()
-        assert state["gateway_state"] == "running"
+        # Alive, but Telegram is parked fatal: a serving-with-a-parked-platform boot is degraded.
+        assert state["gateway_state"] == "degraded"
         assert state["platforms"]["telegram"]["state"] == "fatal"
         assert state["platforms"]["discord"]["state"] == "retrying"
     finally: