Polish admin articles: card grid, thumbnails, author, slug field

Replace the plain articles table with a responsive card grid showing
thumbnails, title, date and author. Add a slug field to the article form
with live auto-suggestion, i18n-driven labels, a larger image preview and
delete confirmation. Persist a user-provided slug (falls back to an
auto-generated one) on create and update.

src/actions/admin-articles.ts

@@ -36,13 +36,14 @@ export async function createArticle(formData: FormData): Promise<void> {
 	const image = String(formData.get("image") ?? "")
 		.normalize("NFC")
 		.trim();
+	const rawSlug = String(formData.get("slug") ?? "").trim();
 	if (!title) return;
 
 	try {
 		const now = new Date();
 		await prisma.websiteArticles.create({
 			data: {
-				slug: await uniqueSlug(title),
+				slug: rawSlug ? await uniqueSlug(rawSlug) : await uniqueSlug(title),
 				title: title.slice(0, 255),
 				shortStory: shortStory.slice(0, 255),
 				fullStory,
@@ -64,6 +65,7 @@ export async function createArticle(formData: FormData): Promise<void> {
 export async function updateArticle(formData: FormData): Promise<void> {
 	await requirePermission(PERMS.NEWS_EDIT);
 	const id = BigInt(String(formData.get("id")));
+	const rawSlug = String(formData.get("slug") ?? "").trim();
 	try {
 		await prisma.websiteArticles.update({
 			where: { id },
@@ -72,6 +74,9 @@ export async function updateArticle(formData: FormData): Promise<void> {
 					.normalize("NFC")
 					.trim()
 					.slice(0, 255),
+				...(rawSlug
+					? { slug: await uniqueSlug(rawSlug) }
+					: {}),
 				shortStory: String(formData.get("shortStory") ?? "")
 					.normalize("NFC")
 					.trim()