fix: use pdf previews for documents

Dockerfile

@@ -25,6 +25,10 @@ RUN apk add --no-cache \
     oniguruma-dev \
     # Pandoc文档转换工具
     pandoc \
+    # LibreOffice用于生成高保真PDF预览，Noto CJK用于中文字体渲染
+    libreoffice \
+    font-noto-cjk \
+    ttf-dejavu \
     # Node.js和npm (使用较小的版本)
     nodejs \
     npm \
@@ -131,4 +135,4 @@ HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
     CMD /usr/local/bin/swoole-health-check.sh || exit 1
 
 # 使用supervisor启动多个服务
-CMD ["/usr/bin/supervisord", "-c", "/etc/supervisor/conf.d/supervisord.conf"]
+CMD ["/usr/bin/supervisord", "-c", "/etc/supervisor/conf.d/supervisord.conf"]