feat: 添加用于运行慢速测试的 npm 脚本

添加 'test:slow' 脚本以专门运行标记为 'Slow' 的 Pester 测试，方便隔离执行耗时较长的测试用例。

Author: mudssky

package.json

@@ -27,6 +27,7 @@
     "test:debug": "pwsh -NoProfile -Command \"\\$env:PWSH_TEST_MODE='debug'; Invoke-Pester -Configuration ( ./PesterConfiguration.ps1 )\"",
     "test:serial:debug": "pwsh -NoProfile -Command \"\\$env:PWSH_TEST_MODE='serial'; \\$env:PWSH_TEST_VERBOSE='1'; Invoke-Pester -Configuration ( ./PesterConfiguration.ps1 )\"",
     "test:profile": "pwsh -NoProfile -Command \"\\$env:PWSH_TEST_MODE='serial'; \\$env:PWSH_TEST_PATH='./tests/ProfileMode.Tests.ps1'; \\$env:PWSH_TEST_VERBOSE='1'; Invoke-Pester -Configuration ( ./PesterConfiguration.ps1 )\"",
+    "test:slow": "pwsh -NoProfile -Command \"\\$c = ./PesterConfiguration.ps1; \\$c.Filter.Tag = 'Slow'; \\$c.Filter.ExcludeTag = @(); Invoke-Pester -Configuration \\$c\"",
     "test:detailed": "pwsh -Command \"Invoke-Pester -Output Detailed\"",
     "scripts:install": "pwsh  -File ./install.ps1",
     "scoop:update": "scoop update -a",