The issue was that new URL().pathname returns Unix-style paths on Windows
(e.g., /D:/a/skillhub/...) which Bun.spawn() cannot resolve correctly.
Using fileURLToPath() converts the URL to a proper platform-specific path.
Changes:
- cli/test/helpers/run-cli.ts: use fileURLToPath for cwd
- cli/test/integration/version-command.test.ts: same fix for build spawn
Bun.which('bun') on Windows CI returns a non-existent path
(C:\Users\runneradmin\.bun\bin\bun.exe), causing all integration
tests to fail. Add existsSync() check to fallback to process.execPath
when the resolved path doesn't exist.
Also fix version-command.test.ts to use process.execPath instead of
hardcoded 'bun' string for cross-platform compatibility.
Fixes 19 failing integration tests on Windows platform.