feat: enhance backend security and configuration

- Updated Dockerfile to improve security with a non-root user and added health checks.
- Modified docker-compose.yml to set containers as read-only, restrict ports to localhost, and implement health checks.
- Enhanced .env.example with additional environment variables for security and configuration.
- Improved FastAPI application with middleware for security headers, CORS, and body size limits.
- Refactored authentication flow in auth.py to include state validation and improved error handling.
- Added rate limiting to various endpoints to prevent abuse.
- Updated researcher and publication handling to ensure better validation and error management.

backend/app/schema/publication.py

@@ -3,6 +3,10 @@ from uuid import UUID
 from typing import Optional, List, Any
 from datetime import datetime
 
+# ---------------------------------------------------------
+# Modelo de publicación
+# ---------------------------------------------------------
+
 class PublicationSchema(BaseModel):
     id: UUID
     put_code: int | None = None