Complete project root and docs/ directory cleanup

- Update all placeholder dates (2024-01-XX → 2024-12-19)
- Create comprehensive DOCUMENTATION_INDEX.md for navigation
- Update README.md with documentation index reference
- Fix LICENSE placeholder text in README
- Add CLEANUP_SUMMARY.md documenting all changes
- Verify no temporary or backup files
- Ensure all cross-references are valid
- Improve documentation organization and navigation

STATUS.md

@@ -1,6 +1,6 @@
 # ASLE Project Status
 
-**Last Updated:** 2024-01-XX  
+**Last Updated:** 2024-12-19  
 **Overall Completion:** 100% ✅
 
 ## Project Overview