fix(ShaderView): Android transparency + correct worklet WebGPU setup (bump rn-webgpu 0.5.15)

[blazejkustra]

What

Fixes the two high-severity issues found while auditing this library's react-native-webgpu × worklets usage, and bumps react-native-webgpu to the latest (0.5.15).

Changes

1. Android transparency was broken

ShaderView used the transparent prop only for the clear color and never forwarded it to <Canvas>. Per the rn-webgpu docs, Android ignores alphaMode — the native transparent prop is what enables a transparent surface there. Transparent effects (e.g. dissolves) therefore rendered on an opaque background on Android.

<Canvas ref={canvasRef} transparent={transparent} ... />

2. Incorrect worklet globals setup (setImmediate override + fragile injection)

The hand-rolled initWebGPU helper injected WebGPU globals into the worklet runtime and, as part of that, did:

globalThis.setImmediate = globalThis.requestAnimationFrame as typeof setImmediate;

The worklet run loop (react-native-worklets ≥ 0.8, enableEventLoop default) already installs a correct setImmediate; overwriting it with requestAnimationFrame changes its semantics (deferred to the next animation-frame flush, passes a timestamp arg). The manual injection also relied on fragile FIFO ordering between two separately-scheduled worklets.

react-native-webgpu@0.5.15 adds the official installWebGPU() entry point — call it once at the top of a worklet to capture the WebGPU flag constants into that runtime. This PR adopts it and removes src/utils/initWebGPU.ts entirely:

scheduleOnRuntime(runtime, () => {
  'worklet';
  installWebGPU(); // idempotent; provides GPUBufferUsage etc. on this runtime
  // ...render
});

This removes the setImmediate override, drops the unused navigator.gpu/self injection, and makes the WebGPU setup run inline in the render worklet (no cross-worklet ordering dependency).

3. Bump

react-native-webgpu 0.5.14 → 0.5.15 (root + example), which is what brings installWebGPU().

Verification

• yarn typecheck ✅
• yarn lint (changed files) ✅
• pre-commit hooks (lint/types/commitlint) ✅

Runtime verification on device/simulator still recommended, especially Android transparency.