feat(utils): add support for ignoring '@eaDir' system files

[xrgzs]

Description / 描述

在 IsSystemFile 中加入对群晖 Synology 系统目录/文件 @eaDir 的忽略支持。

Motivation and Context / 背景

Related to #1634

How Has This Been Tested? / 测试

Running tool: /opt/homebrew/bin/go test -timeout 30s -run ^TestIsSystemFile$ github.com/OpenListTeam/OpenList/v4/pkg/utils

=== RUN   TestIsSystemFile
=== RUN   TestIsSystemFile/.DS_Store
--- PASS: TestIsSystemFile/.DS_Store (0.00s)
=== RUN   TestIsSystemFile/desktop.ini
--- PASS: TestIsSystemFile/desktop.ini (0.00s)
=== RUN   TestIsSystemFile/Thumbs.db
--- PASS: TestIsSystemFile/Thumbs.db (0.00s)
=== RUN   TestIsSystemFile/._test.txt
--- PASS: TestIsSystemFile/._test.txt (0.00s)
=== RUN   TestIsSystemFile/._
--- PASS: TestIsSystemFile/._ (0.00s)
=== RUN   TestIsSystemFile/._somefile
--- PASS: TestIsSystemFile/._somefile (0.00s)
=== RUN   TestIsSystemFile/._folder_name
--- PASS: TestIsSystemFile/._folder_name (0.00s)
=== RUN   TestIsSystemFile/@eaDir
--- PASS: TestIsSystemFile/@eaDir (0.00s)
=== RUN   TestIsSystemFile/test.txt
--- PASS: TestIsSystemFile/test.txt (0.00s)
=== RUN   TestIsSystemFile/file.pdf
--- PASS: TestIsSystemFile/file.pdf (0.00s)
=== RUN   TestIsSystemFile/document.docx
--- PASS: TestIsSystemFile/document.docx (0.00s)
=== RUN   TestIsSystemFile/.gitignore
--- PASS: TestIsSystemFile/.gitignore (0.00s)
=== RUN   TestIsSystemFile/.env
--- PASS: TestIsSystemFile/.env (0.00s)
=== RUN   TestIsSystemFile/_underscore.txt
--- PASS: TestIsSystemFile/_underscore.txt (0.00s)
=== RUN   TestIsSystemFile/normal_file.txt
--- PASS: TestIsSystemFile/normal_file.txt (0.00s)
=== RUN   TestIsSystemFile/#00
--- PASS: TestIsSystemFile/#00 (0.00s)
=== RUN   TestIsSystemFile/.hidden
--- PASS: TestIsSystemFile/.hidden (0.00s)
=== RUN   TestIsSystemFile/..special
--- PASS: TestIsSystemFile/..special (0.00s)
--- PASS: TestIsSystemFile (0.00s)
PASS
ok      github.com/OpenListTeam/OpenList/v4/pkg/utils   0.414s

Checklist / 检查清单

• I have read the CONTRIBUTING document.
  我已阅读 CONTRIBUTING 文档。
• I have formatted my code with go fmt or prettier.
  我已使用 go fmt 或 prettier 格式化提交的代码。
• I have added appropriate labels to this PR (or mentioned needed labels in the description if lacking permissions).
  我已为此 PR 添加了适当的标签（如无权限或需要的标签不存在，请在描述中说明，管理员将后续处理）。
• I have requested review from relevant code authors using the "Request review" feature when applicable.
  我已在适当情况下使用"Request review"功能请求相关代码作者进行审查。
• I have updated the repository accordingly (If it’s needed).
  我已相应更新了相关仓库（若适用）。
  • OpenList-Frontend #XXXX
  • OpenList-Docs #XXXX

[imoldchen]

4.19 版本这个修改并没有生效，在启用 设置 - 全局 - 忽略系统文件 后还是可以看到群晖索引自动生成的目录 @eadir