fix(env): support PowerShell on non-Windows platforms

[nekomoyi]

PowerShell is not Windows-only, but vp env setup was generating env.ps1 with vp.exe. That breaks pwsh users on non-Windows platforms.

Changes

• Replace vp.exe with vp in the generated env.ps1
• Add PowerShell coverage in CLI E2E
• Explicitly identify PowerShell wrapper execution via VP_SHELL_PWSH

[netlify]

✅ Deploy Preview for viteplus-preview canceled.

Name	Link
🔨 Latest commit	1b850ec
🔍 Latest deploy log	https://app.netlify.com/projects/viteplus-preview/deploys/69ef9e1bff9bd00008583ef6

[fengmk2]

@codex review

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. You're on a roll.

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[fengmk2]

@nekomoyi Could you add a corresponding test job in our CI? I'm concerned that future code changes might still modify this code without discovering this special logic.

[nekomoyi]

@fengmk2 Thanks. I’ve updated the PowerShell coverage in CI.

The PowerShell path in our CLI E2E test can now run cross-platform. PowerShell steps go through the shell env wrapper instead of calling the vp binary directly. At the moment, the PowerShell steps are still skipped on namespace-profile-linux-x64-default because that runner does not have pwsh preinstalled.

I also adjusted detect_shell() so that PowerShell wrapper execution is identified by VP_SHELL_PWSH instead of PsModulePath and cfg!(windows).

This fixes the immediate non-Windows pwsh issue, but detect_shell() can still be confused by inherited variables like FISH_VERSION in nested shell scenarios. I’m leaving that for a follow-up with a cleaner approach.