feat: add quarto 1.10 and generate the version lists

[mcanouil]

Follow-up to #160, which was merged before its review fixes landed.

Quarto 1.10. Adds .devcontainer/quarto-1.10/, identical to the other version-pinned configurations apart from the version.

Adding one previously meant editing the build matrix, the configuration table and three prose ranges by hand, so the documentation drifted from .devcontainer/ as soon as one was missed. The build matrix is now derived from the .devcontainer/quarto-* directories, and docs/assets/filters/devcontainer-configurations.lua generates the configuration table and the version ranges from the same directories at render time. Versions sort numerically, so 1.10 follows 1.9 rather than 1.1. Adding a configuration directory is now the only step required.

Review fixes. awk getline returns -1 for a missing or unreadable file and the read loop simply does not run, so a lost artifact would have committed an empty code block to docs/reference/quarto-check.qmd and auto-merged it; the injection now checks the artifact first. The website is rendered on pull requests, so a broken docs change is caught before it reaches main, with the Pages upload and deployment split into their own job so pull request runs neither deploy nor record a deployment. The duplicated target file moves to the job environment, and the .nojekyll step is dropped since it does nothing when Pages is served from an artifact.

Cleanup. The navbar token overrides repeated palette hex values already set in _brand.yml, so the two could drift; they now reference the generated brand Sass variables. The hero, section cards and Codespaces entry points were three copies of one surface, now shared behind placeholders. Both marked sections of the quarto check page are replaced in a single awk pass, verified to produce byte-identical output.