feat: implement core Go application with web server

- Add Go modules with required dependencies (Gin, UUID, JWT, etc.)
- Implement main web server with landing page endpoint
- Add comprehensive API endpoints for health and status
- Include proper error handling and request validation
- Set up CORS middleware and security headers

output/internal/middleware/middleware_fix.go

@@ -0,0 +1,3 @@
+package middleware
+
+// This file can be removed - it's empty and unused