Correctly handle standalone (PWA) mode changes

- Also handle notification permission changes
- Remove web push schedule worker since this complicates
  things and doesn’t do _that_ much. We have the reminder
  notification if the user truly doesn’t reload ntfy in
  more than a week.

web/src/app/Notifier.js

@@ -43,7 +43,7 @@ class Notifier {
     }
   }
 
-  async webPushSubscription() {
+  async webPushSubscription(hasWebPushTopics) {
     if (!this.pushPossible()) {
       throw new Error("Unsupported or denied");
     }
@@ -53,11 +53,11 @@ class Notifier {
       return existingSubscription;
     }
 
-    // Create a new subscription only if Web Push is enabled. It is possible that Web Push
+    // Create a new subscription only if there are new topics to subscribe to. It is possible that Web Push
     // was previously enabled and then disabled again in which case there would be an existingSubscription.
     // If, however, it was _not_ enabled previously, we create a new subscription if it is now enabled.
 
-    if (await this.pushEnabled()) {
+    if (hasWebPushTopics) {
       return pushManager.subscribe({
         userVisibleOnly: true,
         applicationServerKey: urlB64ToUint8Array(config.web_push_public_key),
@@ -119,11 +119,6 @@ class Notifier {
     return this.pushSupported() && this.contextSupported() && this.granted() && !this.iosSupportedButInstallRequired();
   }
 
-  async pushEnabled() {
-    const enabled = await prefs.webPushEnabled();
-    return this.pushPossible() && enabled;
-  }
-
   /**
    * Returns true if this is a HTTPS site, or served over localhost. Otherwise the Notification API
    * is not supported, see https://developer.mozilla.org/en-US/docs/Web/API/notification