Initial controls, states, cascading behavior. Tests use dedicated configs that exercise all 8 control types and 5 state types.
Test plan: 16-initial-settings.md
Footer bar opens to "layers" tab. App bar opens to "legend" tab. A specific layer is pre-selected.
Layer has all 8 controls set to false. No UI buttons/sliders should render for it.
First layer: no controls specified → no query/hover toggles in settings (defaults to false).
Second layer: controls.query/hover = true, states.queryable/hoverable = false → toggles appear but OFF. Toggle ON to verify.
Group → subgroup → child with cascading initialSettings. Parent visible=false, child opacity override, controls.remove=false cascading.