The nginx-property binary's globalValue() switch returned ComputedX for
client-body-timeout, client-header-timeout, keepalive-timeout, and
lingering-timeout, leaking the per-app value into nginx:report's
global-<prop> key. Other properties in the same switch already call
GlobalX. Aligns the four with the rest. Also tightens
tests/unit/nginx-vhosts_properties.bats so the helper preserves values
containing whitespace or literal \$ across the inner /bin/bash -c, and
switches proxy-keepalive to integer values since the set subcommand
validates it via is_number.