Description

The docs build currently leaves several playground links unresolved. Running the docs-only build succeeds, but MkDocs reports that these relative links are not recognized and leaves them as-is.

Expected behavior: links to the hosted playground should resolve cleanly in the generated docs without MkDocs unresolved-link warnings.

Steps to reproduce

uv run --only-group docs mkdocs build --strict

Observed warnings include:

Doc file `index.md` contains an unrecognized relative link `playground/`, it was left as is.
Doc file `development/building.md` contains an unrecognized relative link `../playground/`, it was left as is.
Doc file `reference/instructions.md` contains an unrecognized relative link `../playground/`, it was left as is.

Relevant source links:

• docs/index.md
• docs/development/building.md
• docs/reference/instructions.md

Environment

• Clifft: current main
• OS: not expected to be platform-specific
• Python: 3.12+

Additional context

This should be a small documentation fix. A good solution could use absolute site links, a MkDocs macro/helper, or another approach that works for both the main GitHub Pages site and PR preview builds.

Acceptance criteria:

• Playground links still work in generated docs.
• uv run --only-group docs mkdocs build --strict no longer reports unresolved playground links.