fix(shell): preserve pathname expansion in scripts

[RSS1102]

Motivation

Package scripts rely on platform-specific shell semantics. On Unix, Vite Task's static command path flattened unquoted patterns such as packages/*/src into literal arguments instead of allowing the package-script shell to perform pathname expansion, so vp run behaved differently from package managers.

The task runner should preserve those native semantics without introducing its own cross-platform glob language. Commands that want portable glob behavior can own it explicitly by receiving a quoted pattern unchanged, for example vp lint "packages/*/src".

Fixes #573.

Summary

• preserve unquoted pathname-expansion characters for Unix shell execution
• keep Windows on the static command path because cmd.exe does not expand pathname patterns
• keep quoted, escaped, and assignment-value patterns on the static path for the child command to interpret
• cover parser decisions, execution plans, nested vt run, quoted command-owned patterns, extra arguments, exit codes, and platform-specific behavior with regression tests
• scope the changelog entry to Unix package-script shell expansion

[RSS1102]

@TheAlexLichter

This PR preserves the native package-script behavior on each platform:

• Unix shells expand unquoted globs such as packages/*/src.
• Windows cmd.exe does not expand globs, so the pattern is passed unchanged.
  vp run should not expand globs itself because it cannot know which arguments are file patterns. Portable glob support should be implemented by file-oriented commands such as vp lint.
  Once supported, the cross-platform usage would be:

Windows

"lint": "vp lint \"packages/*/src\""

Quoting ensures that vp lint receives the same pattern on every platform.