Type src/ against API and database shapes, fixing implicit anys

Adds .d.ts declarations beside the untyped JS modules imported from
TS (api.js, navConfig.js, adminSchema.js, adminNav.js, src/data/*),
with shapes taken from the server routes and migrations. get/post/
patch/del now return unknown unless the caller names the response.

Fixes found along the way:
- website/email/instagram are bare strings from splitLinks, not Link
  objects; OrganizationDetail's website and email pills rendered with
  no href or label and now link correctly.
- The chapter map falls back to FALLBACK_COLOR for a region with no
  colour instead of painting its tiles black.

Adds defineSection() so each page manifest entry's props are checked
against its own Component.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/pages/admin/AdminLayout.tsx

@@ -56,8 +56,8 @@ export default function AdminLayout() {
   // What the page below has published about itself — a record
   // name, or null on a list. setDetail is stable so publishing
   // can't loop.
-  const [detail, setDetail] = useState(null);
-  const stableSet = useCallback((value) => setDetail(value), []);
+  const [detail, setDetail] = useState<string | null>(null);
+  const stableSet = useCallback((value: string | null) => setDetail(value), []);
   const titleContext = useMemo(() => ({ setDetail: stableSet }), [stableSet]);
 
   useEffect(() => {