[testing] Published simple_module_test plugin only ships fake_event_bus + build_test_app, not the headline fixtures its README/__init__ advertise #200

Summary

The simple_module_test pytest plugin (installed by consumers) does not provide the db_session / app / client / authenticated_client / settings fixtures that its own README and __init__ advertise — those live only in the framework repo's root conftest.py.

Environment

• Framework checkout: v0.0.17-5-g2b079c9; smpy / published simple_module_* / @simple-module-py/*: 0.0.17
• Python 3.12.3, uv 0.11.7, node v24.15.0, Linux (Ubuntu)

Found while building a real consumer app (Invoice Manager) on the framework.

Evidence

• framework/testing/simple_module_test/plugin.py (the pytest11 entry point) registers only fake_event_bus and build_test_app.
• framework/testing/README.md + simple_module_test/__init__.py describe the headline fixtures as provided by the plugin.

Repro

In a consumer app that depends on simple_module_test (but is not the framework repo), a test using authenticated_client / db_session errors with "fixture not found".

Impact / workaround

A consumer must vendor a root conftest.py re-implementing those fixtures (as laco_wiki_python and this app do). Suggest either moving the headline fixtures into the published plugin, or correcting the README/__init__ to state they're framework-internal.