Fix breaking change: Set server_bundle_output_path default to nil

- Changes default from "ssr-generated" to nil to avoid breaking changes
- Updates documentation to reflect nil default and show example usage
- Feature remains opt-in for backward compatibility
- Can be changed to a sensible default in next major release

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

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

Author: justin808

docs/guides/configuration.md

@@ -131,8 +131,8 @@ ReactOnRails.configure do |config|
 
   # Directory where server bundles will be output during build process.
   # This allows organizing server-side rendering assets separately from client assets.
-  # Default is "ssr-generated"
-  config.server_bundle_output_path = "ssr-generated"
+  # Default is nil (disabled). Set to "ssr-generated" or your preferred directory to enable.
+  # config.server_bundle_output_path = "ssr-generated"
 
   # When enabled, enforces that server bundles are only loaded from secure, designated locations
   # to prevent potential security risks from loading untrusted server-side code.

lib/react_on_rails/configuration.rb

@@ -53,7 +53,7 @@ def self.configuration
       # Set to 0 to disable the timeout and wait indefinitely for component registration.
       component_registry_timeout: DEFAULT_COMPONENT_REGISTRY_TIMEOUT,
       generated_component_packs_loading_strategy: nil,
-      server_bundle_output_path: "ssr-generated",
+      server_bundle_output_path: nil,
       enforce_secure_server_bundles: false
     )
   end