Reapply "Add missing admin action files and navigation links"

This reverts commit 4d515bc400.

src/app/admin/badges/page.tsx

@@ -51,9 +51,7 @@ export default async function AdminBadges({
 
       <section className="mt-6">
         <h2 className="admin-section-title">{t("uploadTitle")}</h2>
-        <p className="text-xs text-[var(--color-text-muted)] -mt-2 mb-3">
-          {t("uploadSubtitle")}
-        </p>
+        <p className="text-xs text-[var(--color-text-muted)] -mt-2 mb-3">{t("uploadSubtitle")}</p>
         <form action={uploadBadge} className="admin-card">
           <div className="flex gap-2 flex-wrap items-center">
             <input type="file" name="file" accept=".gif,.png" required />
@@ -100,7 +98,9 @@ export default async function AdminBadges({
       </section>
 
       <section className="mt-6">
-        <h2 className="admin-section-title">{t("catalogueTitle")} ({badges.length})</h2>
+        <h2 className="admin-section-title">
+          {t("catalogueTitle")} ({badges.length})
+        </h2>
         {badges.length === 0 ? (
           <div className="admin-empty">{t("noBadges")}</div>
         ) : (
@@ -123,10 +123,7 @@ export default async function AdminBadges({
                     <td>{b.badgeName}</td>
                     <td className="text-sm text-gray-500 dark:text-gray-400">{b.badgeDescription}</td>
                     <td>
-                      <form
-                        action={giveBadge}
-                        className="flex gap-2 items-center"
-                      >
+                      <form action={giveBadge} className="flex gap-2 items-center">
                         <input type="hidden" name="code" value={b.badgeKey} />
                         <input
                           name="userId"