Fix Rails 7.1 Zeitwerk eager loading in engine initializer

Rails 7.1 minimum version upgrade exposed timing issue where engine
initializer tried to access job classes before Zeitwerk loaded them.

Problem:
- bin/rails zeitwerk:check failed with "uninitialized constant" errors
- Production environments with config.eager_load = true would fail during boot
- ActiveSupport.on_load(:active_job) hook runs when ActiveJob framework loads,
  but job classes in app/jobs/ may not be loaded yet during eager loading

Solution:
- Replace on_load hook with config.after_initialize
  Ensures all classes are loaded before configuration runs, working correctly
  in both development (autoload) and production (eager load) environments

- Add ShopifyApp:: namespace to job class references
  Required for explicit constant resolution during eager loading

- Add Active Storage config for test dummy app
  Rails 7.1 requires config/storage.yml when eager loading is enabled

Result: bin/rails zeitwerk:check now passes. Engine properly configures
job logging in all loading scenarios.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: lizkenyon

lib/shopify_app/engine.rb

@@ -22,14 +22,12 @@ class Engine < Rails::Engine
       ]
     end
 
-    initializer "shopify_app.redact_job_params" do
-      ActiveSupport.on_load(:active_job) do
-        if ActiveJob::Base.respond_to?(:log_arguments?)
-          WebhooksManagerJob.log_arguments = false
-          ScriptTagsManagerJob.log_arguments = false
-        elsif ActiveJob::Logging::LogSubscriber.private_method_defined?(:args_info)
-          ActiveJob::Logging::LogSubscriber.prepend(RedactJobParams)
-        end
+    config.after_initialize do
+      if ActiveJob::Base.respond_to?(:log_arguments?)
+        ShopifyApp::WebhooksManagerJob.log_arguments = false
+        ShopifyApp::ScriptTagsManagerJob.log_arguments = false
+      elsif ActiveJob::Logging::LogSubscriber.private_method_defined?(:args_info)
+        ActiveJob::Logging::LogSubscriber.prepend(RedactJobParams)
       end
     end
   end

test/dummy/config/storage.yml

@@ -0,0 +1,7 @@
+test:
+  service: Disk
+  root: <%= Rails.root.join("tmp/storage") %>
+
+local:
+  service: Disk
+  root: <%= Rails.root.join("storage") %>