fix cors problem for fart

nginx/html/index.html

@@ -98,7 +98,13 @@
 				// Pre-fetch & decode once (lazy: only on first click)
 				async function initAudio() {
 					ctx = new (window.AudioContext || window.webkitAudioContext)()
-					const res = await fetch(AUDIO_FILE)
+					const res = await fetch(AUDIO_FILE, {
+						method: "GET",
+						mode: "cors", // nur nötig, wenn Domain ≠ Seite
+						headers: {
+							"X-API-Key": API_KEY,
+						},
+					})
 					const array = await res.arrayBuffer()
 					buffer = await ctx.decodeAudioData(array)
 				}