Fix RBS type accuracy and improve error handling

Type Accuracy Fixes:
- Change Configuration#initialize raise_on_prerender_error from bool to bool?
  to allow nil values (matches actual implementation)
- Replace String return types with safe_buffer type alias for methods that
  return html_safe strings (ActiveSupport::SafeBuffer):
  - Helper: react_component, react_component_hash, redux_store,
    redux_store_hydration_data, server_render_js
  - Controller: redux_store_hydration_data
  - Private helpers: build_react_component_result_for_server_rendered_string,
    build_react_component_result_for_server_rendered_hash,
    prepend_render_rails_context

Infrastructure Improvements:
- Improve rake task error handling with explicit case statement for nil
  (handles cases where RBS command is not found)
- Add rubocop disable directive for Metrics/BlockLength in rbs.rake

The safe_buffer type alias (= String) documents that these methods return
html_safe strings while maintaining RBS compatibility without requiring
ActiveSupport type definitions.

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

Co-Authored-By: Claude <noreply@anthropic.com>

Author: justin808

rakelib/rbs.rake

@@ -1,5 +1,6 @@
 # frozen_string_literal: true
 
+# rubocop:disable Metrics/BlockLength
 namespace :rbs do
   desc "Validate RBS type signatures"
   task :validate do
@@ -11,11 +12,15 @@ namespace :rbs do
     # Run RBS validate
     result = system("bundle exec rbs -I sig validate")
 
-    if result
+    case result
+    when true
       puts "✓ RBS validation passed"
-    else
+    when false
       puts "✗ RBS validation failed"
       exit 1
+    when nil
+      puts "✗ RBS command not found or could not be executed"
+      exit 1
     end
   end
 
@@ -30,3 +35,4 @@ namespace :rbs do
     puts "\nTotal: #{sig_files.count} files"
   end
 end
+# rubocop:enable Metrics/BlockLength

sig/react_on_rails/configuration.rbs

@@ -47,7 +47,7 @@ module ReactOnRails
       ?logging_on_server: bool?,
       ?server_renderer_pool_size: Integer?,
       ?server_renderer_timeout: Integer?,
-      ?raise_on_prerender_error: bool,
+      ?raise_on_prerender_error: bool?,
       ?skip_display_none: bool?,
       ?generated_assets_dirs: Array[String]?,
       ?generated_assets_dir: String?,

sig/react_on_rails/controller.rbs

@@ -1,11 +1,15 @@
 module ReactOnRails
   module Controller
+    # Type alias for ActiveSupport::SafeBuffer (html_safe strings)
+    type safe_buffer = String
+
     def redux_store: (
       String store_name,
       ?props: untyped,
       ?immediate_hydration: bool
     ) -> void
 
-    def redux_store_hydration_data: () -> String
+    # Returns html_safe string (ActiveSupport::SafeBuffer)
+    def redux_store_hydration_data: () -> safe_buffer
   end
 end

sig/react_on_rails/helper.rbs

@@ -1,29 +1,37 @@
 module ReactOnRails
   module Helper
+    # Type alias for ActiveSupport::SafeBuffer (html_safe strings)
+    type safe_buffer = String
+
     COMPONENT_HTML_KEY: String
 
     # Main helper methods
+    # Returns html_safe string (ActiveSupport::SafeBuffer)
     def react_component: (
       String component_name,
       ?Hash[Symbol, untyped] options
-    ) ?{ () -> untyped } -> String
+    ) ?{ () -> untyped } -> safe_buffer
 
+    # Returns hash with html_safe strings (ActiveSupport::SafeBuffer)
     def react_component_hash: (
       String component_name,
       ?Hash[Symbol, untyped] options
-    ) ?{ () -> untyped } -> Hash[String, String]
+    ) ?{ () -> untyped } -> Hash[String, safe_buffer]
 
+    # Returns html_safe string (ActiveSupport::SafeBuffer)
     def redux_store: (
       String store_name,
       ?Hash[Symbol, untyped] props
-    ) -> String
+    ) -> safe_buffer
 
-    def redux_store_hydration_data: () -> String
+    # Returns html_safe string (ActiveSupport::SafeBuffer)
+    def redux_store_hydration_data: () -> safe_buffer
 
+    # Returns html_safe string (ActiveSupport::SafeBuffer)
     def server_render_js: (
       String js_expression,
       ?Hash[Symbol, untyped] options
-    ) -> String
+    ) -> safe_buffer
 
     def sanitized_props_string: (untyped props) -> String
 
@@ -43,15 +51,15 @@ module ReactOnRails
       component_specification_tag: String,
       console_script: String,
       render_options: Hash[Symbol, untyped]
-    ) -> String
+    ) -> safe_buffer
 
     def build_react_component_result_for_server_rendered_hash: (
       server_rendered_html: Hash[String, untyped],
       component_specification_tag: String,
       console_script: String,
       render_options: Hash[Symbol, untyped]
-    ) -> Hash[String, String]
+    ) -> Hash[String, safe_buffer]
 
-    def prepend_render_rails_context: (String result) -> String
+    def prepend_render_rails_context: (String result) -> safe_buffer
   end
 end