fix(build): improve Rust toolchain detection on Windows

[FinParker]

No description provided.

[FinParker]

fix(build): improve Rust toolchain detection on Windows, add relevant rustfmt.exe path

[stuuupidcat]

Could you update the CI workflow to include Windows in the matrix? Specifically, please modify the os matrix in https://github.com/RPL-Toolchain/RPL/blob/master/.github/workflows/main.yml#L25, and ensure the tests pass on Windows.

[stuuupidcat]

• Don’t need to run cargo test on Windows anymore—Windows error messages use backslashes, which makes the output inconsistent. Just ensure it builds and runs on Windows.
• Already sent you an invite to the RPL organization; please accept it when you have a moment.

[TheVeryDarkness]

Sorry, I didn't notice this. Let me take a look at it tomorrow.

[Copilot]

Pull Request Overview

This PR enhances Windows compatibility for the RPL toolchain by improving Rust toolchain detection on Windows systems. The changes ensure the build process correctly locates rustfmt.exe on Windows platforms and adds CI testing for Windows.

Key changes:

• Fixed rustfmt executable detection to use .exe extension on Windows
• Added Windows to the CI matrix for continuous testing
• Documented Windows-specific setup requirements

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
crates/rpl_parser/build.rs	Platform-specific rustfmt executable detection for Windows compatibility
README.md	Added Windows-specific installation instructions for RUSTUP_HOME setup
.github/workflows/main.yml	Extended CI to test on Windows and added cargo caching

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[Copilot]

Corrected capitalization of 'Used' to 'used'.

Suggested change

	1. Clone the repository and enter the directory: `git clone https://github.com/RPL-Toolchain/RPL.git && cd RPL` (When Used on Windows, you should first set your RUSTUP_HOME environment variable, normally `%USERPROFILE%\.rustup`)
	1. Clone the repository and enter the directory: `git clone https://github.com/RPL-Toolchain/RPL.git && cd RPL` (When used on Windows, you should first set your RUSTUP_HOME environment variable, normally `%USERPROFILE%\.rustup`)

[Copilot]

The cache paths use Unix-style home directory paths (~/.cargo/) which won't work correctly on Windows. Consider using ${{ runner.tool_cache }} or platform-specific paths, or use a conditional cache configuration per OS.

Suggested change

	~/.cargo/registry
	~/.cargo/git
	${{ runner.os == 'Windows' && env.USERPROFILE || '~' }}/.cargo/registry
	${{ runner.os == 'Windows' && env.USERPROFILE || '~' }}/.cargo/git

[TheVeryDarkness]

It's weird that ''s aren't normalized to '/' by ui-test, and maybe I can debug this on a PC tomorrow or this weekend.

[TheVeryDarkness]

It's weird that ''s aren't normalized to '/' by ui-test, and maybe I can debug this on a PC tomorrow or this weekend.

See config.rs in ui_test.

[TheVeryDarkness]

It seems that the bug has been fixed in ui_test@0.30.2 (previously we're using ui_test@0.29.2). However, there are still some test failures in ui tests