RenderTarget: minor formatting

[epreston]

improve locality of code

Related issue:

Description

move declarations where they are used to populate textures and away from unrelated viewport declaration

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	359.14 85.24	359.14 85.24	+0 B +0 B
WebGPU	621.16 173.09	621.16 173.09	+0 B +0 B
WebGPU Nodes	619.74 172.84	619.74 172.84	+0 B +0 B

🌳 Bundle size after tree-shaking

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

	Before	After	Diff
WebGL	490.85 119.65	490.85 119.64	-6 B -3 B
WebGPU	694.86 188.15	694.85 188.15	-6 B -3 B
WebGPU Nodes	644.06 175.54	644.06 175.54	-6 B -4 B