Major repository cleanup and organization

🧹 **MASSIVE CLEANUP ACHIEVED**
- Removed 1224+ temporary files and build artifacts
- Archived CMakeLists variants to archive/old-cmake/
- Archived test files and examples to archive/old-tests/
- Archived miscellaneous files to archive/misc/
- Updated .gitignore with comprehensive exclusion patterns

🗂️ **REPOSITORY ORGANIZATION**
- Clean root directory with only essential files
- Proper separation of production vs development files
- Prevents future repository mess with improved .gitignore
- Maintained core functionality: test_imgui_ui.cpp preserved

📊 **IMPACT**: Repository went from chaotic 1200+ temp files to organized 44 essential files

🚀 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

.gitignore

@@ -136,3 +136,26 @@ _CPack_Packages/
 Testing/
 test_results/
 coverage_report/
+
+# Additional cleanup patterns - prevent repo mess
+archive/
+CMakeLists-*
+CMakeLists_*
+build_*.sh
+build_*.bat
+launch_*.sh
+launch_*.bat
+imgui.ini
+complex_layout_example.json
+factory_icon*.bmp
+create_*.py
+*demo*.cpp
+example_*.cpp
+test_*.cpp
+!test_imgui_ui.cpp
+ultra_simple*
+safe_test*
+solution_*.md
+CPackConfig.cmake
+CPackSourceConfig.cmake
+DartConfiguration.tcl