Fix Jinja2 template error in Vulkan backend - ensure all messages have content attribute

coderai

@@ -1723,8 +1723,8 @@ async def chat_completions(request: ChatCompletionRequest):
     messages_dict = []
     for msg in messages:
         msg_dict = {"role": msg.role}
-        if msg.content:
-            msg_dict["content"] = msg.content
+        # Always include content key - llama_cpp template expects it
+        msg_dict["content"] = msg.content if msg.content is not None else ""
         if msg.tool_calls:
             msg_dict["tool_calls"] = msg.tool_calls
         if msg.name: