JSDoc: Add custom template.

[Mugen87]

Related issue: -

Description

This PR adds a custom JSDoc template for generating the documentation pages. It uses the fonts, styles and site structure from the original documentation. The template is based on the default JSDoc theme and enhanced with search features from clean-jsdoc-theme.

Page View:

There is now a client-side search:

The sidebar supports two hierarchies as before (category-subcategory). E.g. "Core -> Materials or "Addons -> TSL"

Mobile-View:

Code Sections:

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	336.27 78.29	336.27 78.29	+0 B +0 B
WebGPU	517.16 143.63	517.16 143.63	+0 B +0 B
WebGPU Nodes	516.63 143.52	516.63 143.52	+0 B +0 B

🌳 Bundle size after tree-shaking

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

	Before	After	Diff
WebGL	465.25 112.13	465.25 112.13	+0 B +0 B
WebGPU	589.14 159.74	589.14 159.74	+0 B +0 B
WebGPU Nodes	544.5 149.3	544.5 149.3	+0 B +0 B

[Mugen87]

@mrdoob I'm not a CSS expert but I hope the styles are appropriate. If you think this template is a good replacement for the existing docs, I'll start to migrate the remaining modules in the repository to JSDoc. I'll also add documentation for all Addons which are undocumented so far.

[Mugen87]

Additional notes on the template:

• utils/docs/template/publish.js: This is the main entry point of the template that JSDoc uses to generate the pages. This file also creates the search index.
• utils/docs/template/tmpl/: This directory holds the template files that JSDoc uses to output the markup. layout.tmpl is the main template that holds the HTML root, the JavaScript and CSS includes, and some custom JS.