Consolidate push jobs into single Notification::PushJob

Replace separate WebPushJob and NativePushJob with a single PushJob
that calls notification.push, which iterates over registered targets.
Each target handles its own delivery - Web pushes synchronously via
the pool, Native enqueues device-level jobs via deliver_later_to.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/jobs/notification/push_job.rb

@@ -0,0 +1,5 @@
+class Notification::PushJob < ApplicationJob
+  def perform(notification)
+    notification.push
+  end
+end

app/jobs/notification/web_push_job.rb

@@ -1,5 +0,0 @@
-class Notification::WebPushJob < ApplicationJob
-  def perform(notification)
-    Notification::PushTarget::Web.new(notification).push
-  end
-end

app/models/notification/push_target/web.rb

@@ -1,8 +1,4 @@
 class Notification::PushTarget::Web < Notification::PushTarget
-  def self.push_later(notification)
-    Notification::WebPushJob.perform_later(notification)
-  end
-
   private
     def should_push?
       super && subscriptions.any?

app/models/notification/pushable.rb

@@ -24,8 +24,12 @@ module Notification::Pushable
   end
 
   def push_later
+    Notification::PushJob.perform_later(self)
+  end
+
+  def push
     self.class.push_targets.each do |target|
-      target.push_later(self)
+      target.new(self).push
     end
   end