Add Windows cross-platform support for npm scripts

[ExactDoug]

The current npm scripts use Unix-specific syntax that fails on Windows:

• Environment variables use Unix syntax (VAR=value) instead of cross-platform
• The postinstall script uses Unix 'cp' command which doesn't exist on Windows
• Windows developers cannot run npm scripts natively without WSL

This change adds proper cross-platform support:

1. Added 'cross-env' dependency (v7.0.3)

   • Handles environment variable setting across all platforms
   • Used in: build, electron:dev, website:build scripts

2. Added 'shx' dependency (v0.3.4)

   • Provides Unix commands (like cp) on all platforms
   • Used in: postinstall script

These are industry-standard packages for Node.js cross-platform compatibility.

Scripts updated:

• build: Added cross-env for INLINE_RUNTIME_CHUNK
• postinstall: Changed cp to shx cp for cross-platform file copying
• electron:dev: Added cross-env for BROWSER and ELECTRON_IS_DEV
• website:build: Added cross-env for BUILD_PATH, PUBLIC_URL, INLINE_RUNTIME_CHUNK

This fixes the issues reported in PR #65 and allows Windows developers to run all npm scripts without modification.

[mb21]

Did you test this on Windows yourself? And did you also test it on any other OS?

[ExactDoug]

Did you test this on Windows yourself? And did you also test it on any other OS?

yes. I am only using Windows.

But no. I did not test it on any other OS.

[mb21]

Thanks for the answer. I'm inclined to say Windows devs should just use WSL. I don't have a Windows machine ready to test to properly maintain this.