Bug Report: Windows - Cannot inject the standard library moonbitlang/core

Summary

On Windows, MoonBit CLI v0.1.20260522 fails to load the standard library moonbitlang/core for any project, including freshly created ones via moon new. The error occurs across all build targets (js, wasm, wasm-gc, native).

Version

moon 0.1.20260522 (84aa893 2026-05-22)
Feature flags enabled: rr_moon_mod,rr_moon_pkg

Environment

• OS: Windows 11 (PowerShell / cmd)
• MoonBit installed via: irm https://cli.moonbitlang.cn/install/powershell.ps1 | iex

Reproduction Steps

1. Fresh install MoonBit on Windows
2. Run moon new test_project
3. cd test_project
4. Run moon build --target js (or moon test --target js)

Expected Behavior

Build/test should succeed using the built-in standard library.

Actual Behavior

Error: failed to run build for target Js

Caused by:
    0: Failed to resolve the module dependency graph
    1: Cannot inject the standard library `moonbitlang/core`: Cannot load the core file

Additional Context

• The standard library source does exist at ~/.moon/core/ (cloned from https://github.com/moonbitlang/core, moon.mod present)
• Also tried placing it at ~/.mooncakes/moonbitlang/core/ — same error
• Reinstalling the toolchain via the PowerShell script does not resolve the issue
• The .moon/lib/ directory was temporarily deleted during reinstall; manually restoring runtime_core.c and other files from the ZIP distribution did not help
• All targets fail with the identical error message
• The mooncake CLI does not have an install subcommand to manually fetch core

Suspected Cause

The rr_moon_mod / rr_moon_pkg feature flags may have changed the standard library discovery path on Windows, causing moonc to fail locating/injecting moonbitlang/core.