feat: Implement admin role validation and enhance user management scripts

backend/models/user.py

@@ -20,6 +20,7 @@ class User(BaseModel):
     marked_for_deletion_at: str | None = None
     deletion_in_progress: bool = False
     deletion_attempted_at: str | None = None
+    role: str = 'user'
 
     @classmethod
     def from_dict(cls, d: dict):
@@ -41,6 +42,7 @@ class User(BaseModel):
             marked_for_deletion_at=d.get('marked_for_deletion_at'),
             deletion_in_progress=d.get('deletion_in_progress', False),
             deletion_attempted_at=d.get('deletion_attempted_at'),
+            role=d.get('role', 'user'),
             id=d.get('id'),
             created_at=d.get('created_at'),
             updated_at=d.get('updated_at')
@@ -66,6 +68,7 @@ class User(BaseModel):
             'marked_for_deletion': self.marked_for_deletion,
             'marked_for_deletion_at': self.marked_for_deletion_at,
             'deletion_in_progress': self.deletion_in_progress,
-            'deletion_attempted_at': self.deletion_attempted_at
+            'deletion_attempted_at': self.deletion_attempted_at,
+            'role': self.role
         })
         return base