Reapply "Add missing admin action files and navigation links"

This reverts commit 4d515bc400.

src/actions/admin-radio.ts

@@ -1,27 +1 @@
-'use server';
-
-import { revalidatePath } from 'next/cache';
-import { prisma } from '@/lib/prisma';
-import { requireStaff } from '@/lib/admin/guard';
-
-export async function deleteShout(formData: FormData): Promise<void> {
-  await requireStaff();
-
-  const raw = formData.get('id');
-  if (typeof raw !== 'string' || raw.trim() === '') return;
-
-  let id: bigint;
-  try {
-    id = BigInt(raw);
-  } catch {
-    return;
-  }
-
-  try {
-    await prisma.radioShouts.delete({ where: { id } });
-  } catch {
-    // Row may already be gone; ignore so the action does not throw.
-  }
-
-  revalidatePath('/admin/radio');
-}
+"use server";