Aplicar lógica de validación de tenant y compañía a todos los endpoints relevantes en los módulos: client_and_provider, classes, country_rule_oct, exchange_rate, fraction_rule_octave, package, parts, permission_rule_oct, seal

backend/api/v1/modules/a76/user_tenant/models.py

@@ -1,7 +1,7 @@
 """
 Modelo de relación entre usuarios (Keycloak) y tenants
 """
-from sqlalchemy import Integer, String, DateTime, Boolean, UniqueConstraint, ForeignKeyConstraint
+from sqlalchemy import Integer, String, DateTime, Boolean, UniqueConstraint, ForeignKeyConstraint, ForeignKey
 from sqlalchemy.sql import func
 from sqlalchemy.orm import Mapped, mapped_column, relationship
 from datetime import datetime
@@ -34,6 +34,9 @@ class UserTenant(Base):
     # ID del tenant
     tenant_id: Mapped[int] = mapped_column(Integer, nullable=False, index=True)
     
+    # ID de la empresa asociada
+    company_id: Mapped[int] = mapped_column(Integer, ForeignKey("a76.companies.id"), nullable=False, index=True)
+    
     # Estado de la relación
     is_active: Mapped[bool] = mapped_column(Boolean, default=True, nullable=False)