Reapply "Add missing admin action files and navigation links"

This reverts commit 4d515bc400.

src/actions/article-comments.ts

@@ -21,7 +21,9 @@ export async function postComment(formData: FormData): Promise<void> {
   const userId = Number(session.user.id);
   if (!Number.isFinite(userId)) return;
 
-  const comment = String(formData.get("comment") ?? "").trim().slice(0, COMMENT_MAX);
+  const comment = String(formData.get("comment") ?? "")
+    .trim()
+    .slice(0, COMMENT_MAX);
   if (!comment) return;
 
   // Block filtered/AI-flagged content before it touches the DB (fail-open).