Add experimental Swift-native Sure Insights app (#3134)

* Add Swift-native Sure app

* Fix push subscriptions schema for CI

* Address native app review feedback

* Address remaining native app review feedback

* Use Flutter app logo for native icon

* Honor insight notification preferences and locale

---------

Co-authored-by: Juan Jose Mata <2v8shcb6pz@privaterelay.appleid.com>
Co-authored-by: sure-admin <sure-admin@splashblot.com>

app/controllers/api/v1/push_subscriptions_controller.rb

@@ -0,0 +1,57 @@
+# frozen_string_literal: true
+
+class Api::V1::PushSubscriptionsController < Api::V1::BaseController
+  before_action :ensure_write_scope
+
+  def create
+    token = subscription_params[:token].to_s.downcase
+    subscription = current_resource_owner.push_subscriptions.find_or_initialize_by(token: token)
+    subscription.assign_attributes(
+      environment: subscription_params[:environment],
+      platform: subscription_params[:platform],
+      last_registered_at: Time.current
+    )
+    subscription.save!
+
+    render json: serialize(subscription), status: :created
+  rescue ActiveRecord::RecordInvalid => e
+    render json: { error: "validation_error", message: e.record.errors.full_messages.to_sentence },
+           status: :unprocessable_entity
+  rescue ActiveRecord::RecordNotUnique
+    subscription = current_resource_owner.push_subscriptions.find_by(token: token)
+    if subscription
+      subscription.update!(
+        environment: subscription_params[:environment],
+        platform: subscription_params[:platform],
+        last_registered_at: Time.current
+      )
+      render json: serialize(subscription), status: :created
+    else
+      render json: { error: "validation_error", message: "Device token is already registered" },
+             status: :unprocessable_entity
+    end
+  end
+
+  def destroy
+    current_resource_owner.push_subscriptions.find(params[:id]).destroy!
+    head :no_content
+  end
+
+  private
+    def ensure_write_scope
+      authorize_scope!(:write)
+    end
+
+    def subscription_params
+      params.permit(:token, :environment, :platform)
+    end
+
+    def serialize(subscription)
+      {
+        id: subscription.id,
+        environment: subscription.environment,
+        platform: subscription.platform,
+        last_registered_at: subscription.last_registered_at.iso8601
+      }
+    end
+end