GSOC 26: apply mtl material state to single-material models - #9110

Node.js 20 is deprecated. The following actions target Node.js 20 but are being forced to run on Node.js 24: actions/checkout@11d5960a326750d5838078e36cf38b85af677262, actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020. For more information see: https://github.blog/changelog/2025-09-19-deprecation-of-node-20-on-github-actions-runners/

src/io/csv.js:236:39: Unnecessary escape character '?'

src/io/csv.js:236:36: Unnecessary escape character '*'

src/io/csv.js:236:33: Unnecessary escape character '('

src/io/csv.js:236:30: Unnecessary escape character '{'

src/io/csv.js:236:25: Unnecessary escape character '['

src/webgl/loading.js:759:9: Variable 'hasColorlessVertices' is assigned a value but never used.

src/webgl/loading.js:648:16: Catch parameter 'error' is caught but never used.

src/webgl/loading.js:16:12: Catch parameter 'error' is caught but never used.

src/io/files.js:1149:9: Expected a `break` statement before `case`.