- Add relative path resolution for filesystem-loaded documents in kernel.cpp
- SetDocumentBasePath() tracks document directory for relative resource resolution
- ResolvePath() resolves relative paths like "app.lua" against document base path
- Fix RmlUi context name lookup in sandbox test app (use "default" not "main")
- Add debug logging to timer_manager.cpp to trace timer creation and execution
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>