Add immediate_hydration_config helper to ProUtils

Add a helper method to access the immediate_hydration configuration
from ReactOnRailsPro when Pro is available.

Changes:
- Add immediate_hydration_config class method that returns false
  when Pro is not available, or ReactOnRailsPro.configuration.
  immediate_hydration when Pro is available
- Update disable_pro_render_options_if_not_licensed to use the
  new helper instead of accessing ReactOnRails.configuration

This prepares for removing immediate_hydration from ReactOnRails
configuration.

Author: claude

lib/react_on_rails/pro_utils.rb

@@ -10,6 +10,14 @@ def self.support_pro_features?
       ReactOnRails::Utils.react_on_rails_pro?
     end
 
+    # Returns the immediate_hydration configuration value
+    # @return [Boolean] immediate_hydration setting from Pro config if Pro is available, false otherwise
+    def self.immediate_hydration_config
+      return false unless support_pro_features?
+
+      ReactOnRailsPro.configuration.immediate_hydration
+    end
+
     def self.disable_pro_render_options_if_not_licensed(raw_options)
       return raw_options if support_pro_features?
 
@@ -18,7 +26,8 @@ def self.disable_pro_render_options_if_not_licensed(raw_options)
       PRO_ONLY_OPTIONS.each do |option|
         # Determine if this option is enabled (either explicitly or via global config)
         option_enabled = if raw_options[option].nil?
-                           ReactOnRails.configuration.send(option)
+                           # Use the Pro config helper to get the global config value
+                           immediate_hydration_config
                          else
                            raw_options[option]
                          end