fix(camera): use orbit rotation directly, normalize quaternion each frame

Replace looking_at + with_rotation with a direct rotation assignment —
orbit.rotation already encodes the correct look direction so the
intermediate looking_at call was redundant and discarded. Also re-normalize
the quaternion every frame to prevent floating-point drift from repeated
multiplications.

apps/game/src/camera.rs

@@ -105,6 +105,12 @@ pub fn orbit_camera_control(
             // (local-axis rotation) — this preserves a stable horizon line as
             // long as `rotation` doesn't already pitch past 90°.
             orbit.rotation = yaw * orbit.rotation * pitch;
+
+            // Re-normalize to counteract floating-point drift from repeated
+            // multiplications. Without this the quaternion gradually loses unit
+            // length, introducing an implicit scale that manifests as visual
+            // stretching / skewing of the scene.
+            orbit.rotation = orbit.rotation.normalize();
         }
     } else {
         mouse_motion.clear();
@@ -125,11 +131,13 @@ pub fn orbit_camera_control(
     // the offset is `rotation * +Z * distance`.
     let offset = orbit.rotation * Vec3::new(0.0, 0.0, orbit.distance);
     let position = orbit.target + offset;
-    *transform = Transform::from_translation(position)
+
-        .looking_at(orbit.target, Vec3::Y)
+    // Use `orbit.rotation` directly — it already encodes the correct look
-        // Re-apply rotation to recover the roll component that `looking_at`
+    // direction (rotation * -Z points toward the target). Do NOT call
-        // would otherwise discard (matters when the camera is upside-down).
+    // `looking_at` then `with_rotation`; that computes a correct rotation
-        .with_rotation(orbit.rotation);
+    // only to discard it, and hides the fact that the raw quaternion is the
+    // sole source of truth.
+    *transform = Transform::from_translation(position).with_rotation(orbit.rotation);
 }
 
 /// Resource: set by UI buttons (e.g. "Center View") to request the orbit camera