feat: enforce JSON-only output in generate_response_gpu prompt

app.py

@@ -108,9 +108,10 @@ def generate_response_gpu(prompt, max_tokens=200, temperature=0.7, top_p=0.9):
         return "❌ Model failed to load. Please check the Space logs."
     
     try:
-        # Format input
         formatted_prompt = (
-            f"### Instruction:\n{prompt.strip()}\n\n"
+            "You are a JSON generator. Please output only a valid JSON object and no additional text.\n\n"
+            "### Instruction:\n"
+            f"{prompt.strip()}\n\n"
             "### Response:\n"
         )