This commit implements the parent() function in the Twig template engine,
which allows child templates to access parent template block content when
overriding blocks. The implementation supports:
- Basic single-level parent() calls (child accessing parent content)
- Tracking of original block content through template inheritance chain
- Prevention of infinite recursion in parent() function calls
- Comprehensive test suite for parent() functionality
Future work may include full multi-level inheritance support for nested
parent() calls (child -> parent -> grandparent).
🤖 Generated with [Claude Code](https://claude.ai/code)
Co-Authored-By: Claude <noreply@anthropic.com>
