Eslint: Improve config

[s-rigaud]

Description

I figured out from reading PRs or making one that some eslint rules might be added to the project to improve code quality.

As the core developers will be mainly impacted by the rule changes, you are in a better spot to judge what rules should be added or not. This PR is just a small suggestion.

I updated the code with new rules to get a preview of the changes (there is no error left).

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	339.14 78.99	339.14 78.99	+0 B +0 B
WebGPU	484.69 134.48	484.69 134.48	+0 B +0 B
WebGPU Nodes	484.15 134.38	484.15 134.38	+0 B +0 B

🌳 Bundle size after tree-shaking

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

	Before	After	Diff
WebGL	464.61 111.98	464.61 111.98	+0 B +0 B
WebGPU	553.43 149.79	553.43 149.79	+0 B +0 B
WebGPU Nodes	509.31 139.5	509.31 139.5	+0 B +0 B

[Mugen87]

Do you mind resolving the merge conflicts?