fix(audit): centraliser l'horloge UTC

app/models/user_model/user.py

@@ -1,10 +1,9 @@
 """Base User model — shared fields and polymorphic configuration."""
 
-from datetime import datetime
-
 from flask_login import UserMixin
 
 from app.extensions import db
+from app.time_utils import utc_now_naive
 
 
 class User(UserMixin, db.Model):
@@ -25,7 +24,7 @@ class User(UserMixin, db.Model):
     email = db.Column(db.String(120), unique=True, nullable=False)
     phone = db.Column(db.String(20), nullable=True)
     is_active_account = db.Column(db.Boolean, default=True)
-    created_at = db.Column(db.DateTime, default=datetime.utcnow)
+    created_at = db.Column(db.DateTime, default=utc_now_naive)
 
     failed_login_attempts = db.Column(db.Integer, default=0)
     locked_until = db.Column(db.DateTime, nullable=True)