9c6c5ba0bb
Windows PowerShell 5.1's Out-File -Encoding utf8 prepends a UTF-8 BOM, corrupting the first GITHUB_ENV line so CARGO_WORKSPACE_DIR silently never got set -> windows-reactor build.rs panic -> CI build failed (runs 8765/8768). pwsh 7 writes UTF-8 without a BOM. Installed PowerShell 7.6.2 MSI on the runner and put C:\Program Files\PowerShell\7 on the daemon wrapper PATH so jobs find pwsh; switched all windows.yml steps to shell: pwsh. (Reproduced locally with CARGO_WORKSPACE_DIR set: the build is green in 2m37s — the BOM was the only issue.) Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>