Add read-only iterator support to SchemaTransformer

[staging-devin-ai-integration]

Add read-only iterator support to SchemaTransformer

Summary

Adds read-only iterator support to the SchemaTransformer class to allow clients to iterate over registered rules for introspection purposes. The implementation provides a standard C++ iterator interface with begin(), end(), cbegin(), and cend() methods that return const iterators over the underlying rules map.

Key changes:

• Added const_iterator type alias and iterator methods to SchemaTransformer public interface
• Implemented iterator methods that delegate to the underlying std::map<std::string, std::unique_ptr<SchemaTransformRule>>
• Added comprehensive tests covering empty transformers, rule iteration, direct rule access, and const correctness
• Follows existing patterns from SchemaIterator and JSON container classes in the codebase

The iterator returns key-value pairs where the key is the rule name (string) and the value is a unique_ptr to the SchemaTransformRule. This enables range-based for loops and standard iterator operations for rule introspection.

Review & Testing Checklist for Human

• Test real-world usage: Create a simple test program that uses the iterator to inspect rules in a transformer and verify it meets the actual introspection needs
• Verify thread safety expectations: Check if the broader codebase has any threading considerations that could make iterator invalidation a concern during concurrent rule modifications
• Validate API ergonomics: Confirm that the iterator interface (returning map iterators directly) is intuitive for client code compared to alternatives like custom iterator wrappers

Notes

Session Info: Requested by Juan Cruz Viotti (@jviotti)
Link to Devin run: https://staging.itsdev.in/sessions/573e86fd8e3b4ba1a6ad0b8558225b35

Technical Details:

• All existing tests pass (16/16) and new iterator tests pass (4/4)
• Code formatting and compilation checks completed successfully with make configure compile
• Implementation follows established iterator patterns from SchemaIterator and JSON containers in the codebase
• Iterator exposes the underlying std::map structure directly, which provides full introspection but comes with standard map iterator caveats (invalidation on modification, etc.)

[staging-devin-ai-integration]

🤖 Devin AI Engineer

I'll be helping with this pull request! Here's what you should know:

✅ I will automatically:

• Address comments on this PR. Add '(aside)' to your comment to have me ignore it.
• Look at CI failures and help fix them

Note: I can only respond to comments from users who have write access to this repository.

⚙️ Control Options:

• Disable automatic comment and CI monitoring

[staging-devin-ai-integration]

Closing due to inactivity for more than 7 days. Configure here.