feat: 添加完善的 .gitignore 文件并移除大文件

- 添加根目录 .gitignore 来统一管理忽略规则
- 更新 ljwx-bigscreen 相关的 .gitignore 配置
- 移除超过 GitHub 50MB 限制的大文件
- 忽略日志、缓存、构建输出等文件

ljwx-bigscreen/logs/system_json.log

@@ -1,2 +0,0 @@
-{"timestamp":"2025-06-08T17:02:22.418046","level":"\u001b[32mINFO\u001b[0m","logger":"ljwx.system","module":"bigScreen","function":"<module>","line":121,"message":"Redis连接成功","thread_id":8816713472,"process_id":87223}
-{"timestamp":"2025-06-08T17:02:22.421003","level":"\u001b[32mINFO\u001b[0m","logger":"ljwx.system","module":"debug_control","function":"enable_all_prints","line":22,"message":"已启用所有print调试输出","thread_id":8816713472,"process_id":87223}

ljwx-bigscreen/logs/system_text.log

@@ -1,2 +0,0 @@
-2025-06-08 17:02:22,418 [INFO] ljwx.system.<module>:121 - Redis连接成功
-2025-06-08 17:02:22,421 [INFO] ljwx.system.enable_all_prints:22 - 已启用所有print调试输出