docs(whp): add reference + 5 add-on articles, env.d.ts for font CSS imports

src/env.d.ts

@@ -0,0 +1,5 @@
+/// <reference types="astro/client" />
+
+// Side-effect imports of CSS shipped by @fontsource-variable packages
+declare module '@fontsource-variable/*';
+declare module '@fontsource/*';