[Security] Potential XSS via unsanitized bot_name and bot_description in WebUI

## Security: Potential XSS via unsanitized HTML in WebUI ### Description User-supplied `bot_name` and `bot_description` values are interpolated directly into raw HTML in `qwen_agent/gui/gradio_utils.py` (lines 75-79) without any escaping or sanitization: ```python <div class="bot_name">{bot_name}</div> <div class="bot_desp">{bot_description}</div> ``` ### Reproduction Create an agent with a malicious name: ```python from qwen_agent.gui import WebUI bot = Assistant( llm=llm_cfg, name='<img src=x onerror="alert(document.cookie)">', description='<script>alert("XSS")</script>' ) WebUI(bot).run() ``` Open the Gradio UI — the injected HTML/JS will execute in the browser context. ## Impact An attacker who controls agent configuration (e.g., via a shared config file, API input, or MCP server) can inject arbitrary JavaScript into the WebUI This could lead to session hijacking, credential theft, or UI manipulation Particularly relevant in multi-user or shared deployment scenarios ### Affected File qwen_agent/gui/gradio_utils.py, lines 75-79 ### Severity Medium — requires attacker control over agent configuration, but exploitation is trivial once that condition is met.