Python plugin template

A Python package can extend the in-process registry without changing xtalforge. Declare an entry point in the xtalforge.plugins group:

[project.entry-points."xtalforge.plugins"]
demo = "my_package:register"

def register(registry):
    registry.register_module("demo", lambda parameters: '{"ok": true}')

Then:

import xtalforge.plugins

registry = xtalforge.plugins.default()
print(registry.names_json())

The repository ships a working template in examples/python-plugin: one module and one .demo format. Python entry points are in-process; the Rust plugin registries are the extension point for the CLI and the agent.