fix(three-renderer): keep point symbol geometry local for large coordinates

[mlightcad]

Summary

• Point symbols (dot and line-based display modes) now create geometry at the origin instead of baking world coordinates into vertex data
• World placement is applied via object position on THREE.Points and THREE.LineSegments, consistent with the RTE batch draw policy
• Batched point symbols pass world offset through addGeometry so large-coordinate drawings render correctly
• wcsBbox is computed by translating local geometry bounds to world space
• Added tests covering large-coordinate point symbols in direct and unbatched draw paths

Test plan

• Open a drawing with points at large world coordinates (e.g. UTM/Easting values) and verify point symbols render at the correct locations
• Verify point selection and spatial indexing still work for large-coordinate points
• Run three-renderer tests: pnpm nx test three-renderer --testPathPattern=AcTrPoint