TiledLightsNode: Fix cache-key performance

[sunag]

Related issue: #30062

Description

Improve cache-key performance by removing PointLights cache-key:
There's no need to recreate the shader when adding or removing PointLights in Tiled Lights.

• LightsNode: Fix lights property reference
• webgpu_lights_tiled: Fix normal map tiles

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	339.24 79.02	339.24 79.02	+0 B +0 B
WebGPU	486.17 134.89	486.17 134.89	+1 B -6 B
WebGPU Nodes	485.63 134.79	485.64 134.79	+1 B -3 B

🌳 Bundle size after tree-shaking

Minimal build including a renderer, camera, empty scene, and dependencies.

	Before	After	Diff
WebGL	465.13 112.08	465.13 112.08	+0 B +0 B
WebGPU	555.32 150.32	555.29 150.3	-28 B -21 B
WebGPU Nodes	511.24 140.09	511.21 140.06	-28 B -23 B

[ligaofeng0901]

Hello @sunag
in https://github.com/mrdoob/three.js/blob/dev/examples/jsm/tsl/lighting/TiledLightsNode.js#L71 . The method customCacheKey depends on this._compute, which is initialized in method _create.

But I found customCacheKey is invoked before _create, it cause an error Cannot read properties of null (reading 'getCacheKey')

The example https://github.com/mrdoob/three.js/blob/dev/examples/webgpu_lights_tiled.html works fine because setSize of light node is called in renderLoop in https://github.com/mrdoob/three.js/blob/dev/examples/webgpu_lights_tiled.html#L190