Fix Qwen multimodal prompt content

app.py

@@ -602,7 +602,7 @@ def _generate_qwen38(prompt, max_new_tokens=256, temperature=0.7, thinking=True)
     max_new_tokens = max(1, min(256, int(max_new_tokens)))
     temperature = max(0.0, min(2.0, float(temperature)))
     content = prompt
-    messages = [{"role": "user", "content": content}]
+    messages = [{"role": "user", "content": [{"type": "text", "text": content}]}]
     try:
         text = processor.apply_chat_template(
             messages,