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/db/repositories/publication_repository.py

@@ -1,8 +1,16 @@
 from sqlalchemy.orm import Session
 from app.db.models import Publication
 
+# ---------------------------------------------------------
+# Repositorio de publicaciones
+# ---------------------------------------------------------
+
 class PublicationRepository:
 
+    # ---------------------------------------------------------
+    # Función auxiliar: obtener publicación por put_code
+    # ---------------------------------------------------------
+
     @staticmethod
     def get_by_put_code(db: Session, researcher_id: str, put_code: int):
         """
@@ -17,6 +25,10 @@ class PublicationRepository:
             .first()
         )
 
+    # ---------------------------------------------------------
+    # Función auxiliar: crear una nueva publicación
+    # ---------------------------------------------------------
+
     @staticmethod
     def create(db: Session, researcher_id: str, data: dict):
         """
@@ -37,6 +49,10 @@ class PublicationRepository:
         db.refresh(pub)
         return pub
 
+    # ---------------------------------------------------------
+    # Función auxiliar: actualizar una publicación existente
+    # ---------------------------------------------------------
+
     @staticmethod
     def update(db: Session, publication: Publication, data: dict):
         """
@@ -53,6 +69,10 @@ class PublicationRepository:
         db.refresh(publication)
         return publication
 
+    # ---------------------------------------------------------
+    # Función auxiliar: listar publicaciones de un investigador
+    # ---------------------------------------------------------
+
     @staticmethod
     def list_by_researcher(db: Session, researcher_id: str):
         """