Update skills for Three.js r183

[Jonohobs]

Summary

Updates all 10 skill files and README for Three.js r183 compatibility (from r160+).

Key changes

• Clock deprecated in r183 → Timer recommended throughout (fundamentals, animation)
• BatchedMesh per-instance opacity + wireframe support (geometry)
• OrbitControls programmatic methods (pan/rotate/dolly) + cursorStyle (interaction)
• MeshLambert/Phong now support scene.environment IBL (materials, lighting)
• MeshPhysicalMaterial clearcoat works with rectangular area lights (materials)
• GLTFLoader KHR_meshopt_compression support + getMaterialExtension helper (loaders)
• VRMLLoader camera node support (loaders)
• Scriptable node removed from TSL (shaders, postprocessing)
• retroPass added to post-processing (postprocessing)
• shadowMap.color → shadowMap.transmitted for WebGPU (lighting)
• BezierInterpolant for smooth curve animation (animation)
• KTX2Loader BC3 alpha channel fix + ISO 21496-1 gainmap metadata (textures)
• Matrix4 decompose/invert optimized, camera scale excluded from view matrix (fundamentals)
• Line2NodeMaterial.useColor → vertexColors (materials)
• README version reference updated from r160+ to r183

Test plan

• All code examples syntactically correct
• Import paths match r183 module structure
• Existing valid patterns preserved (additive changes only)
• Manual review of r183 changelog against applied changes

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