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/app/helpers.rs

@@ -345,6 +345,7 @@ pub(super) fn entity_type_key(entity: &acadrust::EntityType) -> String {
         AttributeDefinition(_) => "attdef",
         AttributeEntity(_) => "attrib",
         Ole2Frame(_) => "ole2frame",
+        Light(_) => "light",
         Seqend(_) => "seqend",
         Unknown(_) => "unknown",
     }