202609 repository fixup

[himorin]

fixed various supporting parts

see also immersive-web/administrivia#242

[himorin]

memo: failure from markup validator

$ java -jar "/home/runner/work/_actions/w3c/spec-prod/v2/node_modules/.pnpm/vnu-jar@26.9.7/node_modules/vnu-jar/build/dist/vnu.jar" --also-check-css index.html
      "file:/home/runner/work/model-element/model-element.common/index.html":848.7-848.22: error: Attribute “w-nodev” not allowed on element “div” at this point.
      "file:/home/runner/work/model-element/model-element.common/index.html":870.9-870.12: error: Element “ol” not allowed as child of element “ol” in this context. (Suppressing further errors from this subtree.)
    ❌  Not so good... please fix the issues above.