fix: throw WebGLUnsupportedError when WebGL is unavailable

[dazzatronus]

What changed

• Canvas.load() now throws a typed WebGLUnsupportedError (exported from the package root) when WebGL is unavailable, instead of resolving successfully. The in-canvas error overlay still renders before the throw, so integrations that don't catch keep the current visual behaviour.
• Canvas.resize() is now a no-op when the renderer doesn't exist (before load() completes or after dispose()), instead of throwing TypeError: Cannot read properties of undefined (reading 'resize').

Why

When WebGL is unavailable (hardware acceleration disabled, some VMs/remote desktops), load() silently returned with no renderer. Hosts had no way to detect the failure, treated the editor as loaded, and any subsequent resize() call crashed. Hosts can now catch WebGLUnsupportedError and show their own error state.

Behaviour change

load() rejects where it previously resolved on WebGL-less browsers. Integrations that relied on the silent overlay are unaffected visually, but code awaiting load() should handle the rejection.

How to verify

npx jest tests/webgl-support.test.ts — jsdom has no WebGL, so the tests exercise the real failure path: load() rejects with WebGLUnsupportedError, the overlay still mounts, and resize() no-ops without a renderer.

[github-actions]

🎉 This PR is included in version 2.14.2 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀