docs: reorganize project structure and update root README

Project Organization:
- Moved configuration files to project-config/ directory
- Moved documentation files to documentation/ directory
- Moved security reports to security/ directory
- Moved backup files to backup-config/ directory
- Created PROJECT_ORGANIZATION_SUMMARY.md documenting changes
- Updated all script references to new file locations

Root README Simplification:
- Replaced 715-line detailed README with 95-line structure guide

scripts/setup.sh

@@ -144,8 +144,8 @@ setup_venvs() {
     log "Installing all dependencies from central requirements.txt..."
     
     # Install main requirements (contains all service dependencies)
-    if [ -f "/opt/aitbc/requirements.txt" ]; then
-        pip install -r /opt/aitbc/requirements.txt
+    if [ -f "/opt/aitbc/project-config/requirements.txt" ]; then
+        pip install -r /opt/aitbc/project-config/requirements.txt
     else
         error "Main requirements.txt not found"
     fi