Add Imperative Gesture Handler Testing API

[coado]

Description

The goal is to make gesture lifecycle tests easier to write when we want to assert application state after each gesture step, without requiring users to manually construct RNGH state events with state, oldState, or handlerTag.

Instead of this lower-level style:

fireGestureHandler(panGesture, [
  { oldState: State.UNDETERMINED, state: State.BEGAN },
  { oldState: State.BEGAN, state: State.ACTIVE },
  { oldState: State.ACTIVE, state: State.END },
]);

tests can now use imperative controller:

const gesture = createGestureController(panGesture);

gesture.begin();
expect(onBegin).toHaveBeenCalled();

gesture.activate();
expect(onActivate).toHaveBeenCalled();

gesture.update({ translationX: 50 });
expect(onUpdate).toHaveBeenCalledWith(
  expect.objectContaining({ translationX: 50 })
);

gesture.end();
expect(onFinalize).toHaveBeenCalledWith(
  expect.objectContaining({ canceled: false })
);

Test plan

Added tests using new API.

[Copilot]

Pull request overview

This PR introduces an imperative testing helper (createGestureController) to simplify gesture lifecycle testing in RNGH Jest utilities, enabling step-by-step state transitions and assertions without manually crafting low-level state/oldState events.

Changes:

• Added createGestureController, GestureController, and GestureControllerEvent to drive gesture lifecycles imperatively in tests.
• Exported the new controller API from src/jestUtils/index.ts.
• Added Jest tests covering lifecycle sequencing, validation, testID resolution, and disabled-gesture behavior.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
packages/react-native-gesture-handler/src/jestUtils/jestUtils.ts	Adds the gesture controller implementation and public API surface.
packages/react-native-gesture-handler/src/jestUtils/index.ts	Re-exports the controller types and factory function.
packages/react-native-gesture-handler/src/tests/gestureController.test.tsx	Adds tests validating the new imperative controller behavior.

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