refactor: remove the legacy full view_proj (CPU cull now relative-to-eye)

The GPU draws exclusively via the rotation-only `view_rot` + eye double-
single; the full view-projection survived only to project AABBs in the
CPU frustum-cull / scissor / LOD passes. Migrate those to the same
relative-to-eye math (project `point - eye` through `view_rot`) — pixel-
equivalent but precise at UTM scale — then drop the dead uniform:

- pipeline cull/scissor/LOD helpers take (view_rot, eye) instead of the
  full view_proj; render.rs reconstructs eye from the uniform's
  eye_high/eye_low and passes the cropped view_rot.
- Remove the `view_proj` field from the shared Uniforms struct and all six
  shader structs that only declared it for layout (none read it), and
  delete Camera::view_proj(). The struct shrinks by one mat4 on both
  sides, keeping the Rust / WGSL layouts in lock-step.

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

src/scene/view/camera.rs

@@ -91,28 +91,6 @@ impl Camera {
 
     // ── Projection matrices ────────────────────────────────────────────────
 
-    pub fn view_proj(&self, bounds: Rectangle) -> Mat4 {
-        let aspect = bounds.width / bounds.height;
-
-        // Up vector: use the rotation to find which world direction is "up"
-        // in the current camera frame.
-        let up_dir = self.rotation * Vec3::Y;
-
-        let view = Mat4::look_at_rh(self.eye(), self.target.as_vec3(), up_dir);
-        let proj = match self.projection {
-            Projection::Perspective => {
-                Mat4::perspective_rh(self.fov_y, aspect, self.distance * 0.001, self.distance * 1000.0)
-            }
-            Projection::Orthographic => {
-                let h = self.ortho_size();
-                let w = h * aspect;
-                let (near, far) = self.ortho_depth_range();
-                Mat4::orthographic_rh(-w, w, -h, h, near, far)
-            }
-        };
-        OPENGL_TO_WGPU * proj * view
-    }
-
     /// Orthographic near/far that CENTRE the target plane at ndc-z ≈ 0.5.
     ///
     /// The draw-order depth bias shifts clip-z by ±`DRAW_ORDER_BIAS` (0.001).