Internal cross-references resolve

Broken internal links are a reference-integrity defect: a README that points at docs/api.md after the file moved to docs/reference/api.md tells users the documentation is out of date and unreliable. Dead anchor links, missing image badges, and links to source files that were renamed in a refactor all accumulate after restructures. Each broken link is a dead end in the user's journey, and at scale they collectively destroy the navigability of the docs.

Run a link checker across all documentation files and fix every broken internal reference. Wire the check into CI so new breakage fails the build. Example:

npx markdown-link-check README.md
npx markdown-link-check 'docs/**/*.md'

Update stale paths or delete links whose targets are gone. For anchor links, verify the heading slug still matches after any rename.