fix(scripting): stream_subscribe fails with 'No stream factory registered' in construction T3 eval

[runyaga]

Summary

During construction scheduling T3 (dispatcher) eval runs, stream_subscribe("crew_updates") and stream_subscribe("weather_updates") throw RuntimeError: Invalid argument (name): No stream factory registered in the Monty sandbox.

Reproduction

Run the construction experiment with T3 dispatcher rooms:

dart run packages/soliplex_cli/bin/construction_experiment.dart http://localhost:8000 /tmp/eval 1

T3 rooms use needsStreams: true and the prompt instructs the model to subscribe to crew_updates and weather_updates streams.

Stack trace

MontyScriptEnvironment.collectTextResult (monty_script_environment.dart:118)
MontyScriptEnvironment._executePython (monty_script_environment.dart:60)
_CodeCapturingExtension.tools.<closure> (construction_experiment.dart:347)
AgentSession._executeSingle (agent_session.dart:300)
RunOrchestrator._driveToolLoop (run_orchestrator.dart:332)

Impact

• Model burns 3-5 tool calls retrying before eventually outputting code-as-text (0 captured tool calls)
• T3 verifier then sees incomplete state (jobs not completed, only 2 of 5 assignments)
• The eval still passes because the pre-seeded schedule + state validation is lenient, but the stream processing path is never actually exercised

Expected

Stream factories for crew_updates and weather_updates should be registered via ConstructionPlugin or extraFunctions so the Monty sandbox can subscribe and process events.