feat(help): 重构帮助系统为图片渲染模式

添加浏览器管理器和图片管理器，用于通过 Playwright 渲染帮助菜单为图片
重构命令管理器以支持图片缓存和同步功能
添加 HTML 模板用于帮助菜单渲染

core/managers/image_manager.py

@@ -0,0 +1,115 @@
+"""
+图片生成管理器模块
+
+负责管理图片生成相关的逻辑，支持多种渲染引擎（目前支持 Playwright）。
+"""
+import os
+import base64
+from typing import Dict, Any, Optional
+from jinja2 import Template
+
+from .browser_manager import browser_manager
+from ..utils.logger import logger
+
+class ImageManager:
+    """
+    图片生成管理器（单例）
+    """
+    _instance = None
+
+    def __new__(cls):
+        if cls._instance is None:
+            cls._instance = super().__new__(cls)
+        return cls._instance
+
+    def __init__(self):
+        # 模板目录
+        self.template_dir = os.path.join(os.path.dirname(os.path.dirname(os.path.dirname(__file__))), "templates")
+        # 临时文件目录
+        # core/managers/image_manager.py -> core/managers -> core -> core/data/temp
+        self.temp_dir = os.path.join(os.path.dirname(os.path.dirname(__file__)), "data", "temp")
+        os.makedirs(self.temp_dir, exist_ok=True)
+
+    async def render_template(self, template_name: str, data: Dict[str, Any], output_name: str = "output.png", quality: int = 80, image_type: str = "png") -> Optional[str]:
+        """
+        使用 Playwright 渲染 Jinja2 模板并保存为图片文件
+
+        Args:
+            template_name (str): 模板文件名 (例如 "help.html")
+            data (Dict[str, Any]): 传递给模板的数据字典
+            output_name (str, optional): 输出文件名. Defaults to "output.png".
+            quality (int, optional): JPEG 质量 (0-100). 仅在 image_type 为 jpeg 时有效. Defaults to 80.
+            image_type (str, optional): 图片类型 ('png' or 'jpeg'). Defaults to "png".
+
+        Returns:
+            Optional[str]: 生成图片的绝对路径，如果失败则返回 None
+        """
+        template_path = os.path.join(self.template_dir, template_name)
+        if not os.path.exists(template_path):
+            logger.error(f"模板文件未找到: {template_path}")
+            return None
+
+        try:
+            # 1. 渲染 HTML
+            with open(template_path, "r", encoding="utf-8") as f:
+                template_str = f.read()
+            
+            template = Template(template_str)
+            html_content = template.render(**data)
+
+            # 2. 使用浏览器截图
+            page = await browser_manager.get_new_page()
+            if not page:
+                logger.error("无法获取浏览器页面")
+                return None
+
+            try:
+                # 设置视口
+                await page.set_viewport_size({"width": 650, "height": 100})
+                
+                # 加载内容
+                await page.set_content(html_content)
+                await page.wait_for_selector("body")
+                
+                # 截图
+                screenshot_args = {'full_page': True, 'type': image_type}
+                if image_type == 'jpeg':
+                    screenshot_args['quality'] = quality
+                    
+                screenshot_bytes = await page.screenshot(**screenshot_args)
+                
+            finally:
+                await page.close()
+
+            # 3. 保存文件
+            output_path = os.path.join(self.temp_dir, output_name)
+            with open(output_path, "wb") as f:
+                f.write(screenshot_bytes)
+                
+            logger.info(f"图片已生成: {output_path} ({len(screenshot_bytes)/1024:.2f} KB)")
+            return os.path.abspath(output_path)
+
+        except Exception as e:
+            logger.exception(f"渲染模板 {template_name} 失败: {e}")
+            return None
+
+    async def render_template_to_base64(self, template_name: str, data: Dict[str, Any], output_name: str = "output.png", quality: int = 80, image_type: str = "png") -> Optional[str]:
+        """
+        渲染模板并返回 Base64 编码的图片字符串
+        """
+        file_path = await self.render_template(template_name, data, output_name, quality, image_type)
+        if not file_path:
+            return None
+            
+        try:
+            with open(file_path, "rb") as f:
+                content = f.read()
+            
+            mime_type = "image/jpeg" if image_type == "jpeg" else "image/png"
+            return f"data:{mime_type};base64," + base64.b64encode(content).decode("utf-8")
+        except Exception as e:
+            logger.error(f"读取图片文件失败: {e}")
+            return None
+
+# 全局图片管理器实例
+image_manager = ImageManager()