Describe the bug

When using Mesa’s Solara-based visualization stack with Altair charts fails to render for some of the examples. The Solara UI fails to load entirely and causes a crash.

• So far i have only encountered this issue with only specific models, namely

1. mesa/examples/basic/virus_on_network
2. mesa/examples/basic/boltzmann_wealth_model
3. mesa/examples/advanced/pd_grid
4. mesa/examples/advanced/sugarscape_g1mt

Expected behavior

Altair charts should render correctly in Solara-based Mesa visualizations when following the standard Mesa development setup, without running into UI crashes.

To Reproduce

Environment (example):

• Python: 3.11
• Mesa: main branch (current)
• Altair: 6.0.0 (currently being installed implicitly via pip install -e ".[dev]")
• Solara: 1.30.0 (currently being installed implicitly via `pip install -e ".[dev]")

Steps:

1. Clone the Mesa repository.

2. Install dependencies using:

   pip install -e ".[dev]"

3. Run any Mesa example model that uses Solara + Altair for visualization.

4. Launch the Solara frontend (solara run ... or via the provided example runner).

5. Observe that the Altair charts do not render and the UI crashes.