Add test for rsim#234: no AR default_timezone deprecation warning

Capture deprecation warnings emitted while resolving
plsql.default_timezone with `activerecord_class` set, and assert that
no warning mentioning `default_timezone` was raised.

The test_gemfiles workflow exercises every supported ActiveRecord
version (5.0 through 8.0), so this test will catch any future
regression that re-introduces a call to the deprecated per-class
`default_timezone` accessor on AR 7.0/7.1.

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

Author: yahonda

spec/plsql/schema_spec.rb

@@ -218,6 +218,24 @@ class TestModel < TestBaseModel
     expect(plsql.default_timezone).to eq(:utc)
   end
 
+  it "should not emit ActiveRecord::Base.default_timezone deprecation warning (#234)" do
+    skip "ActiveRecord.default_timezone is not available" unless ActiveRecord.respond_to?(:default_timezone=)
+
+    ActiveRecord.default_timezone = :utc
+
+    deprecator = ActiveRecord.respond_to?(:deprecator) ? ActiveRecord.deprecator : ActiveSupport::Deprecation
+    original_behavior = deprecator.behavior
+    warnings = []
+    begin
+      deprecator.behavior = ->(message, *) { warnings << message }
+      expect(plsql.default_timezone).to eq(:utc)
+    ensure
+      deprecator.behavior = original_behavior
+    end
+
+    expect(warnings.grep(/default_timezone/)).to be_empty
+  end
+
   it "should have the same connection as default schema" do
     expect(plsql.hr.connection).to eq(plsql.connection)
   end