chore: add harness test for dispose during Fabric prop diffing

Rapidly switches RiveView file prop to test that callDispose doesn't
crash React Fabric's prop diffing. Verifies the fix from #227.

Author: mfazekas

example/__tests__/dispose-prop-diffing.harness.tsx

@@ -0,0 +1,96 @@
+import {
+  describe,
+  it,
+  expect,
+  render,
+  cleanup,
+} from 'react-native-harness';
+import { useState, useEffect } from 'react';
+import { View, Text } from 'react-native';
+import {
+  RiveView,
+  useRiveFile,
+  Fit,
+} from '@rive-app/react-native';
+
+const BOUNCING_BALL = require('../assets/rive/bouncing_ball.riv');
+const COUNTER = require('../assets/rive/counter.riv');
+const RATING = require('../assets/rive/rating.riv');
+
+const FILES = [BOUNCING_BALL, COUNTER, RATING];
+
+function RiveBox({ source }: { source: number }) {
+  const { riveFile } = useRiveFile(source);
+
+  return (
+    <View style={{ width: 100, height: 100 }}>
+      {riveFile && (
+        <RiveView file={riveFile} autoPlay fit={Fit.Contain} style={{ flex: 1 }} />
+      )}
+    </View>
+  );
+}
+
+function FileSwitcher({
+  fileIdx,
+}: {
+  fileIdx: number;
+}) {
+  const source = FILES[fileIdx % FILES.length]!;
+  return <RiveBox source={source} />;
+}
+
+describe('dispose during Fabric prop diffing', () => {
+  it('rapidly switching file prop should not crash', async () => {
+    let setIdx: (fn: (i: number) => number) => void;
+
+    function Wrapper() {
+      const [fileIdx, _setIdx] = useState(0);
+      setIdx = _setIdx;
+      return <FileSwitcher fileIdx={fileIdx} />;
+    }
+
+    await render(<Wrapper />);
+
+    // Wait for initial file to load
+    await new Promise((r) => setTimeout(r, 500));
+
+    // Rapid 3x switch — same pattern that crashes on RN 0.83
+    setIdx!((i) => i + 1);
+    await new Promise((r) => setTimeout(r, 50));
+    setIdx!((i) => i + 1);
+    await new Promise((r) => setTimeout(r, 50));
+    setIdx!((i) => i + 1);
+
+    // Wait for everything to settle
+    await new Promise((r) => setTimeout(r, 500));
+
+    // If we get here without crashing, the test passes
+    expect(true).toBe(true);
+
+    cleanup();
+  });
+
+  it('switching file 10 times rapidly should not crash', async () => {
+    let setIdx: (fn: (i: number) => number) => void;
+
+    function Wrapper() {
+      const [fileIdx, _setIdx] = useState(0);
+      setIdx = _setIdx;
+      return <FileSwitcher fileIdx={fileIdx} />;
+    }
+
+    await render(<Wrapper />);
+    await new Promise((r) => setTimeout(r, 500));
+
+    for (let i = 0; i < 10; i++) {
+      setIdx!((j) => j + 1);
+      await new Promise((r) => setTimeout(r, 30));
+    }
+
+    await new Promise((r) => setTimeout(r, 500));
+    expect(true).toBe(true);
+
+    cleanup();
+  });
+});