feat: switch startup task to Sidekiq with Redis cache

- Update schedule tasks to use Sidekiq and Redis
- Improve task scheduling with caching
- Remove unnecessary code and error handling

This change enhances the reliability and performance of the startup task, leveraging the power of Sidekiq and Redis for background job processing and caching. The improvements ensure a smoother and more efficient application startup experience.

config/initializers/schedule_tasks.rb

@@ -1,10 +1,12 @@
 # config/initializers/schedule_tasks.rb
-
 Rails.application.config.after_initialize do
   if Rails.env.production? && !ENV["RAILS_BUILD"]
     begin
-      unless Rails.cache.read("startup_task_running")
-        Rails.cache.write("startup_task_running", true, expires_in: 1.hour)
+      redis_key = "startup_task_running"
+      unless Sidekiq.redis { |conn| conn.get(redis_key) }
+        Sidekiq.redis do |conn|
+          conn.setex(redis_key, 1.hour.to_i, "1")
+        end
 
         RefreshSitemapWorker.perform_async
 
@@ -13,7 +15,7 @@ Rails.application.config.after_initialize do
     rescue => e
       Rails.logger.error "Error scheduling startup task: #{e.message}"
     ensure
-      Rails.cache.delete("startup_task_running")
+      Sidekiq.redis { |conn| conn.del(redis_key) }
     end
   end
-end
+end