Add a 2D plan view for simulation and scenario maps

[JaidenAGrimminck]

The 2d-view work adds a top-down plan view under app/spatial/planview and wires it into the simulation overlay and scenario map.

In progress:

• Frame, projection, transform, selection, and visibility (frame.js, project.js, transform.js, selection.js, visibility.js, usePlanViewFrame.js)
• Layer registry plus actors, controls, goal, heading, lane, localization, perception, route, sensors, signals, speed, trails, and labels
• Hooks in simulation chrome/menu, the vehicle overlay, controls path arc, and ScenarioMapViewport

Done when:

• The plan view draws those layers from the live simulation frame
• Layer visibility and selection work from the simulation menu
• The scenario map and the in-sim overlay stay consistent
• Focused plan-view tests cover frame projection and layer output