Give alias and random suffix for whatsapp videos without created timestamp

app/models.py

@@ -18,6 +18,7 @@ class Video(BaseModel):
     long: Optional[float] = None
     address: Optional[str] = None
     difficulty_level: Optional[str] = Field("Tout niveau", description="Niveau de difficulté")
+    alias: Optional[str] = None
 
     # --- propriétés pratiques ---
     @property
@@ -28,7 +29,7 @@ class Video(BaseModel):
     @property
     def title(self) -> str:
         """Nom court à afficher."""
-        return self.mp4_file_name or self.file_name
+        return self.alias or self.mp4_file_name or self.file_name
     
     @property
     def difficulty_display(self) -> str: