Fix emperor_dilemma: relative imports and outdated SpaceRenderer API

The emperor_dilemma example is currently broken and cannot be run due to two issues:

1. Relative imports in app.py, model.py, and agents.py are incompatible with
how Solara loads example modules.

2. SpaceRenderer.setup_agents() no longer exists in the current Mesa API.

Both issues prevent the example from running at all.

Start by inspecting app.py, model.py, and agents.py to understand how Solara loads the example modules and where SpaceRenderer.setup_agents() is called. Update the incompatible imports and current Mesa API usage, then verify that the emperor_dilemma example runs successfully.

Written by the indexing model from the issue text.