Update doctor.rb to check Pro config for immediate_hydration

Moves immediate_hydration configuration check from ReactOnRails config
analysis to ReactOnRailsPro config analysis. The doctor now reads the
react_on_rails_pro.rb initializer file to display immediate_hydration
settings when the Pro package is configured.

Author: claude

lib/react_on_rails/doctor.rb

@@ -633,6 +633,7 @@ def check_shakapacker_configuration_details
 
     def check_react_on_rails_configuration_details
       check_react_on_rails_initializer
+      check_react_on_rails_pro_initializer
       check_deprecated_configuration_settings
       check_breaking_changes_warnings
     end
@@ -664,6 +665,29 @@ def check_react_on_rails_initializer
       end
     end
 
+    def check_react_on_rails_pro_initializer
+      config_path = "config/initializers/react_on_rails_pro.rb"
+
+      return unless File.exist?(config_path)
+
+      begin
+        content = File.read(config_path)
+
+        checker.add_info("\n📋 React on Rails Pro Configuration:")
+        checker.add_info("📍 Documentation: https://www.shakacode.com/react-on-rails-pro/")
+
+        # Immediate hydration (Pro feature)
+        immediate_hydration_match = content.match(/config\.immediate_hydration\s*=\s*([^\s\n,]+)/)
+        if immediate_hydration_match
+          checker.add_info("  immediate_hydration: #{immediate_hydration_match[1]}")
+        else
+          checker.add_info("  immediate_hydration: false (default)")
+        end
+      rescue StandardError => e
+        checker.add_warning("⚠️  Unable to read react_on_rails_pro.rb: #{e.message}")
+      end
+    end
+
     def analyze_server_rendering_config(content)
       checker.add_info("\n🖥️  Server Rendering:")
 
@@ -732,12 +756,6 @@ def analyze_performance_config(content)
       auto_load_match = content.match(/config\.auto_load_bundle\s*=\s*([^\s\n,]+)/)
       checker.add_info("  auto_load_bundle: #{auto_load_match[1]}") if auto_load_match
 
-      # Immediate hydration (Pro feature)
-      immediate_hydration_match = content.match(/config\.immediate_hydration\s*=\s*([^\s\n,]+)/)
-      if immediate_hydration_match
-        checker.add_info("  immediate_hydration: #{immediate_hydration_match[1]} (React on Rails Pro)")
-      end
-
       # Component registry timeout
       timeout_match = content.match(/config\.component_registry_timeout\s*=\s*([^\s\n,]+)/)
       return unless timeout_match