Revert "feat: replace Web Push with ntfy for medication reminders"

This reverts commit 1cada42370.

public/lib/api.js

@@ -27,5 +27,7 @@ export const api = {
   stats: () => request("/api/stats"),
   roast: () => request("/api/roast"),
   snooze: (slot_id, minutes) => request("/api/snooze", { method: "POST", body: JSON.stringify({ slot_id, minutes }) }),
-  notifyConfig: () => request("/api/notify-config"),
+  vapidKey: () => request("/api/vapid-public-key"),
+  pushSubscribe: (subscription) =>
+    request("/api/push/subscribe", { method: "POST", body: JSON.stringify({ subscription }) }),
 };

public/lib/pwa.js

@@ -46,3 +46,23 @@ export async function registerPwa() {
     console.error("SW registration failed:", e);
   }
 }
+
+export async function subscribePush(vapidPublicKey) {
+  if (!("PushManager" in window)) throw new Error("Push nicht unterstützt");
+  const reg = await navigator.serviceWorker.ready;
+  let sub = await reg.pushManager.getSubscription();
+  if (!sub) {
+    sub = await reg.pushManager.subscribe({
+      userVisibleOnly: true,
+      applicationServerKey: urlBase64ToUint8Array(vapidPublicKey),
+    });
+  }
+  return sub.toJSON();
+}
+
+function urlBase64ToUint8Array(base64String) {
+  const padding = "=".repeat((4 - (base64String.length % 4)) % 4);
+  const base64 = (base64String + padding).replace(/-/g, "+").replace(/_/g, "/");
+  const raw = atob(base64);
+  return Uint8Array.from([...raw].map((c) => c.charCodeAt(0)));
+}