Fix rsc_support_enabled? to return explicit boolean values

Fix the rsc_support_enabled? method to return true/false instead of nil
when enable_rsc_support is false or nil.

Issue: The expression `respond_to?(:enable_rsc_support) && enable_rsc_support`
returns nil when enable_rsc_support is falsy, not an explicit false.

Solution: Use double bang (!!) to coerce the result to a boolean:
`respond_to?(:enable_rsc_support) && !!enable_rsc_support`

This fixes 3 failing tests:
- ReactOnRailsPro::Utils.rsc_support_enabled? when RSC support is enabled
- ReactOnRailsPro::Utils.rsc_support_enabled? when RSC support is disabled
- ReactOnRailsPro::Utils cache helpers .bundle_hash and .bundle_file_name

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

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

Author: AbanoubGhadban

react_on_rails_pro/lib/react_on_rails_pro/utils.rb

@@ -51,7 +51,7 @@ def self.rsc_support_enabled?
       return @rsc_support_enabled if defined?(@rsc_support_enabled)
 
       rorp_config = ReactOnRailsPro.configuration
-      @rsc_support_enabled = rorp_config.respond_to?(:enable_rsc_support) && rorp_config.enable_rsc_support
+      @rsc_support_enabled = rorp_config.respond_to?(:enable_rsc_support) && !!rorp_config.enable_rsc_support
     end
 
     # Validates the license and raises an exception if invalid.