feat(scene): draw nonprint light, camera and geo-location glyphs

Lights, camera views and the geographic-location marker had no on-screen
representation. Add display glyphs for all three:

- Lights render through a new EntityType::Light: a cone/flashlight for spot
  lights, a wire sphere for point lights, a sun for distant lights, sized in
  screen space (fixed-world fallback).
- Camera views (perspective VIEW records) and the GEODATA "daisy" marker are
  synthesized into the model-space resident wire set from the document, since
  they are not entities.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/scene/convert/tessellate.rs

@@ -421,6 +421,7 @@ pub fn tessellate(
     // Relative-PDSIZE points size their glyph from the current zoom so they
     // stay a roughly constant on-screen size; otherwise the header-driven path.
     let te = crate::entities::point::relative_truck(entity, document, world_per_pixel)
+        .or_else(|| crate::entities::light::relative_truck(entity, document, world_per_pixel))
         .or_else(|| convert(entity, document));
     if let Some(te) = te {
         match te.object {