Update app.py

app.py

@@ -255,7 +255,7 @@ def generate_dissertation_api():
                 types.Part.from_bytes(data=image_bytes, mime_type=mime_type)
             ]
             # Utiliser le modèle multimodal 1.5
-            model_name = "models/gemini-1.5-flash"
+            model_name = "models/gemini-2.5-flash"
 
         else: # Type 1 et 2 (texte uniquement)
             context_str = ""