Y-up worlds in the camera: an up axis on the camera (Z by default, or Y), with yaw and pitch measured about it; standard views, the home view, Look At, orbit, pan, the ground grid (XZ with Y up), the ground shadow and snapshots follow it. ui upAxis setting (app.set_up_axis re-aims and frames); cam.up_dir / to_frame / from_frame for the view cube and others

Part of #3 (the camera half; the preference and import offer are shell's)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RjGw4gA5ZvKrU8MQP6sBgT

crates/render/src/lib.rs

@@ -7,5 +7,5 @@
 mod camera;
 mod raster;
 
-pub use camera::{Camera, CameraAnim, Mat4, Quat, StandardView, ease_in_out};
+pub use camera::{Camera, CameraAnim, Mat4, Quat, StandardView, UpAxis, ease_in_out};
 pub use raster::{Canvas, Rgb, Scene, SceneLine, SceneMesh, png, render, render_png, render_transparent};