Reapply "Add missing admin action files and navigation links"

This reverts commit 4d515bc400.

src/app/badges/page.tsx

@@ -20,11 +20,7 @@ export default async function BadgesPage() {
 
   return (
     <main style={{ display: "grid", gap: "1.5rem" }}>
-      <ContentCard
-        icon="🏅"
-        title={t("title")}
-        subtitle={t("subtitle")}
-      />
+      <ContentCard icon="🏅" title={t("title")} subtitle={t("subtitle")} />
 
       <ContentCard padded={badges.length === 0}>
         {badges.length === 0 ? (