feat: add support for custom helper names via js_helper_name parameter

[devjoaov]

Description 📖

This pull request adds support for customizing generated helper names in routes using a new js_helper_name parameter. This allows developers to override the automatic helper name generation and maintain consistent naming patterns across polymorphic controllers and complex route structures.

Background 📜

This was happening because the automatic helper name generation creates inconsistent names for polymorphic controllers. For example, with an admin_update_logs controller that handles both receipts and referrals, the generated helpers were:

export default {
  index: /* #__PURE__ */ definePathHelper('get', '/admin/v2/receipts/:receipt_id/admin_update_logs'),
  adminV2ReferralAdminUpdateLogs: /* #__PURE__ */ definePathHelper('get', '/admin/v2/referrals/:referral_id/admin_update_logs'),
}

The first route gets a generic index name while the second gets a verbose auto-generated name, creating inconsistency in the JavaScript API and making it harder to maintain a predictable naming pattern across related routes.

The Fix 🔨

By changing the generator to check for a js_helper_name parameter in route defaults before falling back to automatic name generation:

def helper
  js_helper_name = @route.defaults[:js_helper_name]
  return js_helper_name if js_helper_name.present?

  # existing automatic generation logic...
end

And allowing developers to specify custom names in their routes:

Rails.application.routes.draw do
  namespace :admin do
    namespace :v2 do
      resources :receipts do
        resources :admin_update_logs, only: [:index], js_helper_name: "adminV2ReceiptAdminUpdateLogs"
      end
      
      resources :referrals do
        resources :admin_update_logs, only: [:index], js_helper_name: "adminV2ReferralAdminUpdateLogs"
      end
    end
  end
end

This now generates consistent, descriptive helper names:

export default {
  adminV2ReceiptAdminUpdateLogs: definePathHelper('get', '/admin/v2/receipts/:receipt_id/admin_update_logs'),
  adminV2ReferralAdminUpdateLogs: definePathHelper('get', '/admin/v2/referrals/:referral_id/admin_update_logs'),
}

The fix maintains backward compatibility while giving developers full control over helper naming for complex route structures and polymorphic controllers.

[ElMassimo]

Hi there! I like the idea of being able to customize the route name explicitly, but I'd prefer if it was nested under the export option, as the features added in #50.

For example:

resources :admin_update_logs, only: [:index], export: {helper: "adminV2ReceiptAdminUpdateLogs"}