Fix pnpm warning handling in installer

[MallyDev2]

What changed

• Runs installer commands through the native command shim instead of the PowerShell pnpm shim.
• Keeps pnpm warnings visible in the installer output without treating warning text as a PowerShell script failure.
• Rebuilt release assets with the updated installer script.

Checks

• npm run check
• PowerShell parser check
• npm run build