Enable Ruby warnings in CI test runs

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: yahonda

.github/workflows/test.yml

@@ -84,4 +84,4 @@ jobs:
         bundle install --jobs 4 --retry 3
     - name: Run RSpec
       run: |
-        bundle exec rspec
+        RUBYOPT=-w bundle exec rspec

.github/workflows/test_11g.yml

@@ -85,4 +85,4 @@ jobs:
         bundle install --jobs 4 --retry 3
     - name: Run RSpec
       run: |
-        bundle exec rspec
+        RUBYOPT=-w bundle exec rspec