Default continue-on-error of the test step to false

No job sets matrix.ignore-error, so when the tests failed GitHub reported an invalid template with "Unexpected value ''" instead of the failure itself.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: hsbt

.github/workflows/ci.yml

@@ -55,7 +55,7 @@ jobs:
       - run: bundle exec rake build
 
       - run: bundle exec rake test
-        continue-on-error: ${{ matrix.ignore-error }}
+        continue-on-error: ${{ matrix.ignore-error || false }}
 
       - name: Integration test
         run: bundle exec rake check