v0.9.0

[0.9.0 - 2026-09-29]

Added

• New affn::transform module with typed inter-reference-system transforms
  Transform<FromCenter, FromFrame, ToCenter, ToFrame, Op> wrapping existing
  affine operators (Rotation3, Translation3, Isometry3).
• Shape-specialized Transform::new on valid operator/tag combinations only
  (frame-only Rotation3, center-only Translation3, rigid Isometry3).
• op, into_op, apply, Mul<Position>, then, and inverse for applying
  and composing typed transforms.
• Operator composition via ComposeAfter (then applies self first, then
  next; mixed rotation/translation pairs promote to Isometry3).
• Convenience aliases FrameTransform, CenterTransform, and RigidTransform.
• Compile-fail rustdoc examples for invalid shapes, non-AffineCenter usage,
  mismatched application, and incompatible composition.

Notes

• Transform lives at affn::transform::Transform (not re-exported from the
  crate root or prelude).

• Center-changing transforms require AffineCenter with Params = ().
  Frame-only Rotation3 transforms accept any ReferenceCenter and preserve
  parameterized center_params.

• Use fully-qualified Transform::<…>::new(op) when the compiler cannot infer
  the transform shape from context.

• Re-export qtty as affn::qtty so consumers can use the exact quantity types from affn's public API without a separate direct qtty dependency (#27).