- Test pre-canceled tokens return immediately for all animation methods
- Test animations complete normally without cancellation
- Cover FadeToAsync, RotateToAsync, RotateXToAsync, RotateYToAsync
- Cover ScaleToAsync, ScaleXToAsync, ScaleYToAsync
- Cover TranslateToAsync, RelRotateToAsync, RelScaleToAsync

Preserve original method signatures as forwarding overloads to maintain
binary compatibility. Add new overloads with required CancellationToken
parameter. Remove *REMOVED* entries from PublicAPI files since original
signatures are preserved.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

The entries with 'CancellationToken cancellationToken = default(...)' don't
match any actual method signature. The real methods have CancellationToken
as a required parameter without a default value.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

- Wrap CancellationToken.Register callbacks in DispatchIfRequired to ensure
  AbortAnimation is called on the UI thread in both AnimateToAsync and
  TranslateToAsync, preventing cross-thread access to the animation system
- Change tcs.SetResult to tcs.TrySetResult in the finished callback to
  prevent InvalidOperationException when CT fires concurrently with completion
- Add TOCTOU guard after Commit() to handle tokens canceled between the
  Register and Commit calls
- Add FadeToAsyncCanceledMidFlightReturnsCanceled test exercising in-flight
  cancellation with AsyncTicker

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Use single-arg Prepare overload (matching all other tests in file).
The prior two-arg form had handler/box variable names swapped,
causing a compile error when using box as VisualElement.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…TOCTOU guards

- Replace fixed Task.Delay(64) in FadeToAsyncCanceledMidFlightReturnsCanceled with
  a polling loop (up to 5s) that waits until opacity actually decreases, eliminating
  timing-dependent flakiness on loaded CI machines
- Wrap v.AbortAnimation() calls in TOCTOU guards (AnimateToAsync and TranslateToAsync)
  with DispatchIfRequired(), consistent with the cancellation callback path

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…rameter

The single-arg Prepare<T>(T view) method was hardcoded to create
AnimationReadyHandler() (BlockingTicker) instead of using the TTicker
generic parameter from the enclosing class. This caused
FadeToAsyncCanceledMidFlightReturnsCanceled to fail on CI because
the animation completed synchronously before the test could observe
mid-flight state.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>