feat(web): unify fonts and refine viewcube

Preload one language-aware font resource across the interface, drawing text, and navigation labels.\n\nRender the navigation cube, ring, outlines, and labels through a 4x MSAA target.

src/scene/mod.rs

@@ -130,7 +130,7 @@ pub use pick::selection_state::SelectionState;
 pub use pipeline::uniforms::Uniforms;
 pub use pipeline::viewcube::{
     hit_test, hit_test_cardinal, hover_id, CubeRegion, NudgeDir, VIEWCUBE_DRAW_PX, VIEWCUBE_PAD,
-    VIEWCUBE_PX, VIEWCUBE_REGION_PX,
+    VIEWCUBE_PX, VIEWCUBE_REGION_PX, VIEWCUBE_RENDER_PX,
 };
 use view::camera::Camera;
 pub use view::camera::Projection;