• Analyze the issue in DefinitionLoader.cs where GetProperty() doesn't find inherited properties
• Fix the AttachInputs method to use BindingFlags to include inherited properties
• Create a custom step inheriting from Foreach for testing
• Create a test case that reproduces the issue and verifies the fix
• Verify the fix works and all tests pass
• Run existing tests to ensure no regression
• Fix build issue with test using incorrect WorkflowRegistry instantiation

Summary

Fixed the YAML deserializer issue where custom step types inheriting from built-in steps (like Foreach) couldn't bind to inherited properties.

Root Cause: In DefinitionLoader.cs line 225, stepType.GetProperty(input.Key) only looks for properties declared in the exact type, not in base classes.

Solution: Changed to stepType.GetProperty(input.Key, BindingFlags.Public | BindingFlags.Instance) which includes inherited public instance properties.

Build Fix: Updated the integration test to use A.Fake<IWorkflowRegistry>() instead of new WorkflowRegistry() to follow the existing test patterns and resolve the missing type reference.

Test Coverage: Added integration test that verifies both:

1. Inherited properties like RunParallel from Foreach can now be bound in custom step types
2. Truly unknown properties still throw appropriate exceptions

The fix is minimal and surgical - only one line changed to use the proper BindingFlags overload. All existing tests pass, confirming no regression.

Fixes #1375.

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