The Windows dry-run failure prints an error (which passes the
install/skill/mcp/agent check) but no "dry-run" indicator, and the
smoke never echoed the captured output on THIS branch, so the actual
error stayed hidden. Echo it. (Root: Windows install routes through
cli_windows_managed_install, which errors on launcher/payload source
verification before emitting a dry-run plan - the next run will name
which check fails.)
Signed-off-by: Martin Vogel <martin.vogel.tech@gmail.com>