feat: complete SDK wrapper cancellation_token propagation

- Update AsyncScenarioRun.await_env_ready to pass cancellation_token
- Completes cancellation support across all SDK polling operations

Part of porting TypeScript PR #765 features to Python SDK.

Author: tode-rl

src/runloop_api_client/sdk/async_scenario_run.py

@@ -106,7 +106,11 @@ async def await_env_ready(
         :return: Scenario run state after environment is ready
         :rtype: ScenarioRunView
         """
-        await self._client.devboxes.await_running(self._devbox_id, polling_config=options.get("polling_config"))
+        await self._client.devboxes.await_running(
+            self._devbox_id,
+            polling_config=options.get("polling_config"),
+            cancellation_token=options.get("cancellation_token"),
+        )
         return await self.get_info(**filter_params(options, BaseRequestOptions))
 
     async def score(