Curling the sibling container's own bridge-network IP (the previous
fix) doesn't work on this runner -- docker-outside-of-docker means the
job container's network namespace can't reach another container's
bridge IP directly, so every curl attempt hung for the full ~130s TCP
SYN timeout instead of failing fast (confirmed: a run got stuck for
over 10 minutes on this). 127.0.0.1 does work here (the monorepo's own
build.yml has published a host port successfully all along), so
publish one again, but to a per-run PID-derived port instead of a
fixed one, to still avoid the original port-collision problem.
emi
b4690a0a5e