Fix: transformer trait override Issue 1119

[rodrigobnogueira]

Summary

Fixes #1119 - Transformer not used with trait and value override

When a field has both a base Transformer and a Trait that overrides it with another Transformer, user-provided overrides were bypassing the base transformer entirely when the trait was not active.

Root Cause

When a Trait wraps a field, it replaces the declaration with a Maybe that selects between the trait's value (yes_declaration) and the base value (no_declaration). However, Maybe didn't propagate the CAPTURE_OVERRIDES attribute from its branches, so user overrides would replace the entire Maybe declaration instead of being forwarded to the appropriate transformer.

Solution

Added CAPTURE_OVERRIDES propagation from no_declaration in Maybe.__init__. This ensures that when the trait is NOT active and there's a base Transformer, user overrides are properly forwarded to the base transformer.

self.CAPTURE_OVERRIDES = getattr(no_declaration, 'CAPTURE_OVERRIDES', False)

The fix specifically uses no_declaration (not both branches with or) to preserve the existing behavior where user overrides bypass the trait's transformer when the trait IS active.

Testing

• 2 new regression tests added to tests/test_transformer.py
• Full test suite passes (449 tests)
• Tests cover both trait-inactive and trait-active scenarios

Checklist

• Tests pass locally
• New tests added for new functionality
• Follows existing code style
• Linting passes