Use the existing pinned cross-spawn dependency at the command-spawn boundary instead of forcing every Windows executable and argument vector through cmd.exe. Preserve native executable arguments while retaining PATH/PATHEXT and command-shim support.
Validation: public runner argv and lock/cancellation tests passed on POSIX. Windows-only tests cover an executable path with spaces, bare node, npm, and the local turbo shim; native Windows execution remains unverified.
Fixes#2319
fd9588089d