Re-enable API caching

5 minute cache, forcing revalidate when stale. May up this during
FWA or other cons. I'm expecting as time goes on fursona endpoints
stabilise and are updated less often, letting me increase this further.

api/[domain]/fursona.ts

@@ -29,7 +29,7 @@ export default async (request: Request) => {
 	return new Response(JSON.stringify(data), {
 		headers: {
 			'content-type': 'application/json'
-			//  'cache-control': 'public, max-age=600, stale-while-revalidate=1200',
+			'cache-control': 'public, max-age=300, must-revalidate',
 		}
 	});
 };