feat: replace Web Push with ntfy for medication reminders

Single notification path via ntfy HTTP publish for reliable Android delivery;
remove VAPID, push subscriptions, and SW push handlers. PWA settings show
topic subscribe link; humor texts and deep-link actions unchanged.

Co-authored-by: Cursor <cursoragent@cursor.com>

public/lib/api.js

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