Create experiment to paint textures in browser using canvases

[cnotv]

After playing with materials, it seemed that most of the textures are just 2 colors, while classic textures can be an image, as done for billboards.
Update the editor to allow just certain colors and automatically set one by default to the brush.
Create a config panel with all the textures and allow editing all of them as is done in MultiplayerP2P.
Store textures in localstorage.
The view should just be a ball. Config panel should contain all the material options as done for the MaterialList, without repeating code, so abstract some logic.

[cnotv]

Implementation Plan

Changes

• src/utils/materialBuilder.ts — Extract buildMaterial from MaterialsList into a shared utility (takes textures + envMap as params)
• src/views/Experiments/MaterialsList/MaterialsList.vue — Import buildMaterial from shared util
• src/views/Experiments/TexturePainter/TexturePainter.vue — Main view: Three.js sphere + material config panel + texture editors via Teleport
• src/views/Experiments/TexturePainter/config.ts — View constants; re-uses DEFAULT_CONFIG, CONFIG_SCHEMA, getEnabledMaps from materialsListConfig
• src/config/viewsMeta.json — Add 'Texture Painter' entry

Approach

1. Shared material builder — Move buildMaterial from MaterialsList.vue to src/utils/materialBuilder.ts so both views use the same logic without duplication.
2. TexturePainter view — Single sphere in a Three.js orthographic scene. Config panel (via registerViewConfig) exposes a material type ButtonSelector + all material properties (wireframe, roughness, metalness, etc.) identical to MaterialsList config.
3. Texture editors — A CanvasEditor per texture (diffuse, normal, roughness, ao, displacement, emissive) injected into #config-panel-extra via <Teleport> (same pattern as MultiplayerP2P). Each texture has a limited 2-color palette per texture type (the brush color is controlled from preset swatches, no free picker).
4. Persistence — Texture data URLs saved to localStorage using storageSaveLocal/storageLoadLocal from @webgamekit/canvas-editor. Textures are restored on mount and applied to the sphere material.
5. Sphere rotation — Drag to rotate, click to cycle material type (same as MaterialsList showcase).

Questions

• For the texture editor palette: should each texture have exactly 2 preset colors (e.g. normal = #8080ff + #404080, roughness = #ffffff + #000000) or allow more colors?