WebGLRenderer: sRGB decoding for VideoTexture emissiveMap.

[donmccurdy]

Implements inline sRGB decoding when a VideoTexture is used as the .emissiveMap for built-in materials.

Related:

• Fixes VideoTexture’s colorSpace not working on Emissive channel #29625
• Related VideoTexture: Restore inline sRGB decode. #26521

Workaround for browser issues:

• https://issues.chromium.org/issues/40915685
• https://bugs.webkit.org/show_bug.cgi?id=222822

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	689.92 170.93	690.29 171.01	+368 B +78 B
WebGPU	814.88 219.41	814.88 219.41	+0 B +0 B
WebGPU Nodes	814.39 219.28	814.39 219.28	+0 B +0 B

🌳 Bundle size after tree-shaking

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

	Before	After	Diff
WebGL	462.94 111.81	463.31 111.89	+368 B +76 B
WebGPU	537.7 145.08	537.7 145.08	+0 B +0 B
WebGPU Nodes	493.81 134.81	493.81 134.81	+0 B +0 B