feat: implement pivot-currency model, rbac smart tokens & fix circular imports

backend/app/models/core_logic.py

@@ -1,7 +1,8 @@
 from sqlalchemy import Column, Integer, String, ForeignKey, Boolean, DateTime, JSON, Numeric
 from sqlalchemy.orm import relationship
 from sqlalchemy.sql import func
-from app.db.base import Base
+# JAVÍTVA: Import közvetlenül a base_class-ból
+from app.db.base_class import Base
 
 class SubscriptionTier(Base):
     __tablename__ = "subscription_tiers"
@@ -39,4 +40,4 @@ class ServiceSpecialty(Base):
     name = Column(String, nullable=False)
     slug = Column(String, unique=True)
 
-    parent = relationship("ServiceSpecialty", remote_side=[id], backref="children")
+    parent = relationship("ServiceSpecialty", remote_side=[id], backref="children")