refactor: modernize registration prompt notification in ContactQRScanShowView

- Replace deprecated notify.confirm() with modern $notify() API
- Add structured notification object with group, type, and title properties
- Extract registration prompt response logic into reusable handleRegistrationPromptResponse method
- Update settings method from $updateSettings to $saveSettings for consistency
- Align implementation with ContactsView.vue for better code consistency

This brings the registration prompt notification in ContactQRScanShowView up to parity with the modern implementation used in ContactsView.

src/views/ContactQRScanShowView.vue

@@ -738,24 +738,17 @@ export default class ContactQRScanShow extends Vue {
         !contact.registered
       ) {
         setTimeout(() => {
-          this.notify.confirm(
-            "Do you want to register them?",
+          this.$notify(
             {
+              group: "modal",
+              type: "confirm",
+              title: "Register",
+              text: "Do you want to register them?",
               onCancel: async (stopAsking?: boolean) => {
-                if (stopAsking) {
-                  await this.$updateSettings({
-                    hideRegisterPromptOnNewContact: stopAsking,
-                  });
-                  this.hideRegisterPromptOnNewContact = stopAsking;
-                }
+                await this.handleRegistrationPromptResponse(stopAsking);
               },
               onNo: async (stopAsking?: boolean) => {
-                if (stopAsking) {
-                  await this.$updateSettings({
-                    hideRegisterPromptOnNewContact: stopAsking,
-                  });
-                  this.hideRegisterPromptOnNewContact = stopAsking;
-                }
+                await this.handleRegistrationPromptResponse(stopAsking);
               },
               onYes: async () => {
                 await this.register(contact);
@@ -885,6 +878,17 @@ export default class ContactQRScanShow extends Vue {
       videoElement.style.transform = shouldMirror ? "scaleX(-1)" : "none";
     }
   }
+
+  private async handleRegistrationPromptResponse(
+    stopAsking?: boolean,
+  ): Promise<void> {
+    if (stopAsking) {
+      await this.$saveSettings({
+        hideRegisterPromptOnNewContact: stopAsking,
+      });
+      this.hideRegisterPromptOnNewContact = stopAsking;
+    }
+  }
 }
 </script>