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/security.py

@@ -0,0 +1,44 @@
+import enum
+import uuid
+from datetime import datetime, timedelta
+from sqlalchemy import Column, Integer, String, DateTime, ForeignKey, JSON, Enum, text
+from sqlalchemy.orm import relationship
+from sqlalchemy.sql import func
+from app.db.base_class import Base
+
+class ActionStatus(str, enum.Enum):
+    pending = "pending"   # Jóváhagyásra vár
+    approved = "approved" # Végrehajtva
+    rejected = "rejected" # Elutasítva
+    expired = "expired"   # Lejárt (biztonsági okokból)
+
+class PendingAction(Base):
+    """Négy szem elv: Műveletek, amik jóváhagyásra várnak."""
+    __tablename__ = "pending_actions"
+    __table_args__ = {"schema": "data"}
+
+    id = Column(Integer, primary_key=True, index=True)
+    
+    # Ki akarja csinálni?
+    requester_id = Column(Integer, ForeignKey("data.users.id"), nullable=False)
+    
+    # Ki hagyta jóvá/utasította el?
+    approver_id = Column(Integer, ForeignKey("data.users.id"), nullable=True)
+    
+    status = Column(Enum(ActionStatus), default=ActionStatus.pending, nullable=False)
+    
+    # Milyen típusú művelet? (pl. "CHANGE_ROLE", "WALLET_ADJUST", "DELETE_LOGS")
+    action_type = Column(String(50), nullable=False)
+    
+    # A művelet adatai JSON-ben (pl. {"user_id": 5, "new_role": "admin"})
+    payload = Column(JSON, nullable=False)
+    
+    # Miért kell ez a művelet? (Indoklás kötelező az audit miatt)
+    reason = Column(String(255), nullable=False)
+
+    created_at = Column(DateTime(timezone=True), server_default=func.now())
+    expires_at = Column(DateTime(timezone=True), default=lambda: datetime.now() + timedelta(hours=24))
+    processed_at = Column(DateTime(timezone=True), nullable=True)
+
+    requester = relationship("User", foreign_keys=[requester_id])
+    approver = relationship("User", foreign_keys=[approver_id])