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>

server/settings.py

@@ -10,9 +10,10 @@ class Settings(BaseSettings):
     jwt_secret: str = "dev-secret-change-me"
     jwt_expire_days: int = 90
 
-    vapid_private_key: str = ""
-    vapid_public_key: str = ""
-    vapid_claims_email: str = "mailto:admin@schwenk.online"
+    ntfy_url: str = "https://ntfy.schwenk.online"
+    ntfy_topic: str = "takeyourmeds"
+    ntfy_token: str = ""
+    ntfy_click_url: str = "https://medis.schwenk.online"
 
     openrouter_api_key: str = ""
     openrouter_model: str = "google/gemini-2.0-flash-001"