Refactor immediate_hydration handling and add deprecation warnings

Address code review feedback:

1. Extract duplicated warning message to shared utility method
   - Add ReactOnRails::Utils.immediate_hydration_pro_license_warning helper
   - Replace inline warning messages in controller, helper, and render_options

2. Add deprecation warning for config.immediate_hydration
   - Add getter/setter methods that log deprecation warnings
   - Direct users to remove the deprecated config from initializers
   - Maintains backward compatibility while guiding migration

3. Fix inconsistent nil handling in render_options.rb
   - Simplify immediate_hydration method logic
   - Use consistent pattern: explicit value first, then default to Pro status
   - Remove confusing mix of hash access methods

All changes maintain backward compatibility while improving code
maintainability and providing better user guidance.

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

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

Author: justin808

lib/react_on_rails/configuration.rb

@@ -66,6 +66,26 @@ class Configuration
                   :component_registry_timeout,
                   :server_bundle_output_path, :enforce_private_server_bundles
 
+    # Deprecated: immediate_hydration configuration has been removed
+    def immediate_hydration=(value)
+      Rails.logger.warn <<~WARNING
+        [REACT ON RAILS] The 'config.immediate_hydration' configuration option is deprecated and no longer used.
+        Immediate hydration is now automatically enabled for React on Rails Pro users.
+        Please remove 'config.immediate_hydration = #{value}' from your config/initializers/react_on_rails.rb file.
+        See CHANGELOG.md for migration instructions.
+      WARNING
+    end
+
+    def immediate_hydration
+      Rails.logger.warn <<~WARNING
+        [REACT ON RAILS] The 'config.immediate_hydration' configuration option is deprecated and no longer used.
+        Immediate hydration is now automatically enabled for React on Rails Pro users.
+        Please remove any references to 'config.immediate_hydration' from your config/initializers/react_on_rails.rb file.
+        See CHANGELOG.md for migration instructions.
+      WARNING
+      nil
+    end
+
     # rubocop:disable Metrics/AbcSize
     def initialize(node_modules_location: nil, server_bundle_js_file: nil, prerender: nil,
                    replay_console: nil, make_generated_server_bundle_the_entrypoint: nil,

lib/react_on_rails/controller.rb

@@ -17,11 +17,7 @@ module Controller
     def redux_store(store_name, props: {}, immediate_hydration: nil)
       # If non-Pro user explicitly sets immediate_hydration: true, warn and override to false
       if immediate_hydration == true && !ReactOnRails::Utils.react_on_rails_pro?
-        Rails.logger.warn <<~WARNING
-          [REACT ON RAILS] Warning: immediate_hydration: true requires a React on Rails Pro license.
-          Store '#{store_name}' will fall back to standard hydration behavior.
-          Visit https://www.shakacode.com/react-on-rails-pro/ for licensing information.
-        WARNING
+        Rails.logger.warn ReactOnRails::Utils.immediate_hydration_pro_license_warning(store_name, "Store")
         immediate_hydration = false
       elsif immediate_hydration.nil?
         immediate_hydration = ReactOnRails::Utils.react_on_rails_pro?

lib/react_on_rails/helper.rb

@@ -160,11 +160,7 @@ def react_component_hash(component_name, options = {})
     def redux_store(store_name, props: {}, defer: false, immediate_hydration: nil)
       # If non-Pro user explicitly sets immediate_hydration: true, warn and override to false
       if immediate_hydration == true && !ReactOnRails::Utils.react_on_rails_pro?
-        Rails.logger.warn <<~WARNING
-          [REACT ON RAILS] Warning: immediate_hydration: true requires a React on Rails Pro license.
-          Store '#{store_name}' will fall back to standard hydration behavior.
-          Visit https://www.shakacode.com/react-on-rails-pro/ for licensing information.
-        WARNING
+        Rails.logger.warn ReactOnRails::Utils.immediate_hydration_pro_license_warning(store_name, "Store")
         immediate_hydration = false
       elsif immediate_hydration.nil?
         immediate_hydration = ReactOnRails::Utils.react_on_rails_pro?

lib/react_on_rails/react_component/render_options.rb

@@ -100,17 +100,15 @@ def immediate_hydration
 
         # If non-Pro user explicitly sets immediate_hydration: true, warn and override to false
         if explicit_value == true && !ReactOnRails::Utils.react_on_rails_pro?
-          Rails.logger.warn <<~WARNING
-            [REACT ON RAILS] Warning: immediate_hydration: true requires a React on Rails Pro license.
-            Component '#{react_component_name}' will fall back to standard hydration behavior.
-            Visit https://www.shakacode.com/react-on-rails-pro/ for licensing information.
-          WARNING
+          warning = ReactOnRails::Utils.immediate_hydration_pro_license_warning(react_component_name, "Component")
+          Rails.logger.warn warning
           return false # Force fallback to standard hydration
         end
 
-        options.fetch(:immediate_hydration) do
-          ReactOnRails::Utils.react_on_rails_pro?
-        end
+        # Return explicit value if provided, otherwise default based on Pro license
+        return explicit_value unless explicit_value.nil?
+
+        ReactOnRails::Utils.react_on_rails_pro?
       end
 
       def to_s

lib/react_on_rails/utils.rb

@@ -14,6 +14,12 @@ module Utils
       Rainbow('To see the full output, set FULL_TEXT_ERRORS=true.').red
     } ...\n".freeze
 
+    def self.immediate_hydration_pro_license_warning(name, type = "Component")
+      "[REACT ON RAILS] Warning: immediate_hydration: true requires a React on Rails Pro license.\n" \
+        "#{type} '#{name}' will fall back to standard hydration behavior.\n" \
+        "Visit https://www.shakacode.com/react-on-rails-pro/ for licensing information."
+    end
+
     # https://forum.shakacode.com/t/yak-of-the-week-ruby-2-4-pathname-empty-changed-to-look-at-file-size/901
     # return object if truthy, else return nil
     def self.truthy_presence(obj)