Added site functions

src/lib/content/dates.ts

@@ -0,0 +1,5 @@
+export function parseDate(value: string | null): Date | null {
+  if (!value) return null
+  const date = new Date(/(z|[+-]\d\d:\d\d)$/i.test(value) ? value : `${value}Z`)
+  return Number.isNaN(date.getTime()) ? null : date
+}