- Add .gitkeep files to maintain empty toolbox-* directories in git - Update top-level QWEN.md with project-wide guidelines - Refine ToolboxStack/QWEN.md removing redundant content - Add .gitkeep files to: toolbox-base, toolbox-docstack, toolbox-etl, toolbox-gis, toolbox-lifecycle-buildandtest, toolbox-lifecycle-packageandrelease, toolbox-weather