Reapply "Add missing admin action files and navigation links"

This reverts commit 4d515bc400.

src/app/admin/radio/embed/embed-snippet.tsx

@@ -1,6 +1,6 @@
-'use client';
+"use client";
 
-import { useState } from 'react';
+import { useState } from "react";
 
 /**
  * Read-only copy box for an embed snippet. Renders the code inside a
@@ -27,28 +27,24 @@ export function EmbedSnippet({
       // Clipboard API unavailable (e.g. insecure context) — fall back to
       // selecting the textarea so the user can copy manually.
       const el = document.getElementById(
-        `snippet-${title.replace(/\s+/g, '-').toLowerCase()}`,
+        `snippet-${title.replace(/\s+/g, "-").toLowerCase()}`,
       ) as HTMLTextAreaElement | null;
       el?.select();
     }
   }
 
-  const id = `snippet-${title.replace(/\s+/g, '-').toLowerCase()}`;
-  const lines = snippet.split('\n').length;
+  const id = `snippet-${title.replace(/\s+/g, "-").toLowerCase()}`;
+  const lines = snippet.split("\n").length;
 
   return (
     <section className="mt-6">
       <div className="flex items-center justify-between gap-4 mb-1">
         <h2 className="m-0 text-base font-bold text-[var(--color-text)]">{title}</h2>
         <button type="button" className="btn btn-primary" onClick={copy}>
-          {copied ? 'Copied!' : 'Copy'}
+          {copied ? "Copied!" : "Copy"}
         </button>
       </div>
-      {description ? (
-        <p className="text-xs text-gray-500 dark:text-gray-400 mb-3">
-          {description}
-        </p>
-      ) : null}
+      {description ? <p className="text-xs text-gray-500 dark:text-gray-400 mb-3">{description}</p> : null}
       <textarea
         id={id}
         readOnly