docs: generate each subsystem's cordis surface into its own page; delete the flat catalogs

Rebuild of the region machinery (PR3) on the post-#904 Typert projection:
renderPageRegion/renderInheritedPage live in dsh-typert-generator beside the
projection; scripts/gen-cordis-catalog.ts owns the curated SERVICE_PAGE /
EVENT_SCOPE_PAGE / SERVICE_WALK_EXEMPTIONS / LINK_MAP partition (fail-loud in
both directions, with the independent Context-merge scan backstopping the
projection's blind spot), spliceRegion, and the guarded pair auto-record.
docs/cordis-catalog/ is deleted: the flat events/services catalogs dissolve
into per-page regions and docs/cordis-catalog/core moves to docs/cordis-api/
with the inherited tier as its own generated page. The partition absorbs the
post-regrouping surface: ctx.typert → invariants.md, ctx.directoryPicker →
workspace.md, skills/* events → skills.md, and the four launcher-provided tui
accessor values join the named exemptions.

scripts/project-doc-site.ts

@@ -131,6 +131,12 @@ function destinationRange(rawNode: string, type: 'link' | 'image' | 'definition'
   return { start, end: rawNode.length }
 }
 
+// `#fragment` suffixes pass through verbatim. Generated cordis-surface
+// headings carry explicit `<a id>` anchors with the GitHub slug, so those
+// fragments resolve on the published site too; hand-written headings rely on
+// VitePress's own slugger, which differs from GitHub's for punctuation-heavy
+// text — hand-authored cross-page fragments should prefer plain-text headings
+// or explicit anchors.
 function splitTarget(url: string): { path: string; suffix: string } {
   const boundary = url.search(/[?#]/)
   if (boundary === -1) return { path: url, suffix: '' }