feat: SuperAdmin bootstrap, i18n sync fix and AssetAssignment ORM fix

- Fixed AttributeError in User model (added region_code, preferred_language)
- Fixed InvalidRequestError in AssetAssignment (added organization relationship)
- Configured STATIC_DIR for translation sync
- Applied Alembic migrations for user schema updates

backend/app/models/translation.py

@@ -1,5 +1,6 @@
 from sqlalchemy import Column, Integer, String, Text, Boolean, UniqueConstraint
-from app.db.base import Base
+# JAVÍTÁS: Közvetlenül a base_class-ból importálunk, hogy elkerüljük a körkörös importot
+from app.db.base_class import Base 
 
 class Translation(Base):
     __tablename__ = "translations"
@@ -12,4 +13,4 @@ class Translation(Base):
     key = Column(String(100), nullable=False, index=True)
     lang_code = Column(String(5), nullable=False, index=True)
     value = Column(Text, nullable=False)
-    is_published = Column(Boolean, default=False) # Publikálási állapot
+    is_published = Column(Boolean, default=False)