Two bugs made the first CI run fail with 'waiting for connection:
context deadline exceeded':
1. Container started without --network landed on default bridge,
while job containers run on git_default -> name unresolvable,
bridge IP unreachable cross-network.
2. moby/buildkit default entrypoint only listens on a unix socket.
driver: remote needs TCP. Added --addr tcp://0.0.0.0:8375 and
changed endpoint from docker-container://name (only valid for
the docker-container driver) to tcp://name:8375.
Both verified on the oracle host: buildx remote driver connects,
Status running, platforms linux/arm64,v7,v6.