[Feature][Python] Implement EventListener in python sdk

[twosom]

Linked issue: #687

Purpose of change

This PR implements the EventListener mechanism for both Java and Python runtimes, ensuring API consistency across different language SDKs. It enables developers to monitor and react to events synchronously during the agent's event lifecycle.

Tests

ok

API

Documentation

• doc-needed
• doc-not-needed
• doc-included

[wenjin272]

Hi, @twosom. Thanks for supporting EventListener in python sdk.

Overall, I think the current design has become somewhat overly complex. In my view, we should have a single PythonEventListenerWrapper that, at runtime, uses pemja to instantiate the corresponding Python EventListener object and simply invokes its on_event method.

I think some of the current complexity stems from supporting str(MyPythonListener). Could we use a standard Python fully-qualified class name ("my_module.MyPythonListener") as the listener identifier, instead of the str(MyPythonListener) → "module:qualname.method_name" protocol?

That would let us drop EventListenerMeta, _resolve_module, the <locals> / __main__ / sys.modules fallbacks, and the matching split(":") on the Java side — Python-side instantiation collapses to importlib.import_module + getattr + rpartition(".").

The cost is that listeners must live at module top level (which the PR already enforces against <locals>) and can't be defined in __main__.

Additionally, I believe there is no need to support event listeners in the local_runner. In fact, we are also considering whether the local_runner still needs to exist

Additionally, I believe the current testing is insufficient. We have some unit tests, but no end-to-end tests. For this cross-language scenario, we need to add real tests that submit jobs to the remote environment in e2e_tests_resource_cross_language.