Fix Ruby version to match CI and .ruby-version

Update Ruby version back to 3.4.6 to match .ruby-version file and CI
configuration, ensuring consistency across all environments.

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

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

Author: justin808

Gemfile

@@ -3,7 +3,7 @@
 source "https://rubygems.org"
 git_source(:github) { |repo| "https://github.com/#{repo}.git" }
 
-ruby "3.4.3"
+ruby "3.4.6"
 
 gem "react_on_rails", "16.1.1"
 gem "shakapacker", "9.3.2"