extract_markdown only emitted heading nodes + contains edges and never parsed
link syntax, so a doc full of [text](./other.md) links (index.md,
table-of-contents.md) had no edges to the docs it links and never became a hub.
Add a deterministic link pass: inline, reference-style, and [[wikilinks]],
resolved relative to the source file, external URLs/anchors/images skipped, with
the target id built via the same _make_id recipe so the edge merges onto the
real doc node instead of an orphan.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Safi
e6eaad3d7e