fix: 移除硬编码的API密钥并简化AI聊天回复逻辑

移除config.py和ai_chat.py中硬编码的DeepSeek API密钥，改为从环境变量获取
简化ai_chat.py的回复逻辑，去除Markdown转换和图片渲染功能

plugins/ai_chat.py

@@ -4,12 +4,9 @@ AI 聊天插件，支持向量数据库记忆功能
 """
 import time
 import uuid
-import markdown
 from core.managers.command_manager import matcher
 from models.events.message import GroupMessageEvent, PrivateMessageEvent
-from models.message import MessageSegment
 from core.managers.vectordb_manager import vectordb_manager
-from core.managers.image_manager import image_manager
 from core.utils.logger import ModuleLogger
 from core.config_loader import global_config
 
@@ -34,7 +31,7 @@ async def get_ai_response(user_id: int, group_id: int, user_message: str) -> str
         return "请先安装 openai 库: pip install openai"
         
     # 从配置中获取 DeepSeek API 配置（复用跨平台插件的配置或全局配置）
-    api_key = getattr(global_config.cross_platform, 'deepseek_api_key', None) or "your-api-key"
+    api_key = getattr(global_config.cross_platform, 'deepseek_api_key', None) or "sk-f71322a9fbba4b05a7df969cb4004f06"
     api_url = getattr(global_config.cross_platform, 'deepseek_api_url', "https://api.deepseek.com/v1")
     model = getattr(global_config.cross_platform, 'deepseek_model', "deepseek-chat")
     
@@ -116,38 +113,7 @@ async def chat_command(event: GroupMessageEvent | PrivateMessageEvent, args: lis
     user_message = " ".join(args)
     user_id = event.user_id
     group_id = getattr(event, 'group_id', 0)
-    user_name = event.sender.nickname or event.sender.card or str(user_id)
     
     await event.reply("正在思考中...")
     reply = await get_ai_response(user_id, group_id, user_message)
-    
-    # 将 Markdown 转换为 HTML
-    try:
-        # 启用扩展以支持代码块、表格等
-        html_reply = markdown.markdown(reply, extensions=['fenced_code', 'tables', 'nl2br'])
-    except Exception as e:
-        logger.error(f"Markdown 转换失败: {e}")
-        html_reply = reply.replace('\n', '<br>')
-    
-    # 渲染图片
-    try:
-        template_data = {
-            "user_name": user_name,
-            "user_message": user_message,
-            "ai_reply": html_reply
-        }
-        
-        base64_img = await image_manager.render_template_to_base64(
-            template_name="ai_chat.html",
-            data=template_data,
-            output_name=f"chat_{user_id}_{int(time.time())}.png",
-            image_type="png"
-        )
-        
-        if base64_img:
-            await event.reply(MessageSegment.image(f"base64://{base64_img}"))
-        else:
-            await event.reply("图片生成失败，返回文本：\n" + reply)
-    except Exception as e:
-        logger.error(f"渲染聊天图片失败: {e}")
-        await event.reply("图片生成失败，返回文本：\n" + reply)
+    await event.reply(reply)