Update file inclusion paths in multiple PHP files: Adjusted paths to use the new backend directory structure, ensuring consistent access to functions and configuration files across the application.

backend/.gitignore

@@ -0,0 +1,23 @@
+# Dependencies
+node_modules/
+
+# Build Output (nur in main branch)
+# dist/
+
+# Logs
+*.log
+npm-debug.log*
+
+# OS
+.DS_Store
+Thumbs.db
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+
+# Temporäre Dateien
+*.tmp
+*.temp