fix(web): decode textures as sRGB in 3D viewers

TextureLoader leaves colorSpace as NoColorSpace, so card, tile, token, model, and part art is uploaded as linear and then double-decoded in the shader, washing out contrast. Mark each texture sRGB so the GPU decodes it once, correctly.

apps/web/src/components/viewers/TileMesh.tsx

@@ -69,6 +69,11 @@ export function TileMesh({
 }) {
   const texture: THREE.Texture | null = url ? useTexture(assetUrl(url)) : null;
 
+  // Tile art is sRGB-encoded; `TextureLoader` leaves `colorSpace` as
+  // `NoColorSpace`, which double-decodes it in the shader and washes out
+  // contrast. Mark it sRGB so the GPU decodes it once, correctly.
+  if (texture) texture.colorSpace = THREE.SRGBColorSpace;
+
   // Build the extruded geometry from the tile shape. When `stretch` is false
   // and a texture is available, scale the shape to the image's aspect ratio so
   // the tile matches the source proportions instead of being square. Shared