Windows: absolute glob expansion fails in ls() and CliArguments

[tsavo-at-pieces]

Problem

Absolute glob expansion fails on Windows in two places:

• test/ls_test.dart: ls() an absolute glob expands to absolute paths
• test/cli_arguments_test.dart: globbing with glob: true an absolute glob expands to absolute paths

In CI, expected expanded files are not returned; the pattern is treated as a literal *.txt path.

Reproduction

• Run: https://github.com/open-runtime/dart_cli_script/actions/runs/22376939954
• windows-x64 job: https://github.com/open-runtime/dart_cli_script/actions/runs/22376939954/job/64769258023
• windows-arm64 job: https://github.com/open-runtime/dart_cli_script/actions/runs/22376939954/job/64769258042

Suspected root cause

Glob patterns are being constructed/handled with Windows path separators (\\) instead of POSIX-style separators (/) expected by the glob package parser.

Expected behavior

When glob: true, absolute patterns on Windows should expand to matching absolute file paths, same as Linux/macOS semantics.

Proposed approach

1. Normalize glob pattern input to POSIX-style separators before constructing Glob(...).
2. Ensure ls() and CliArguments follow the same normalization strategy.
3. Add explicit Windows tests for:
   • absolute glob expansion
   • Windows-style backslash input normalization

Acceptance criteria

• Both failing absolute-glob tests pass on windows-x64 and windows-arm64
• Existing Linux/macOS glob tests remain green
• No regressions in non-glob argument parsing