Migrate the state-friendly start/stop tests to the Scenario DSL:
- TestStartStop: stop halts containers in place, start brings the same
ones back (NotRecreated); the ls checks match the project name exactly
in the JSON output, immune to the prefix collisions the other
start-stop project names would cause under parallel runs.
- TestStartStopWithDependencies: dependency start/stop propagation read
from container state instead of 'Container X Started' messages.
- TestUpNoDeps replaces the 'Up no-deps links' subtest as its own
scenario: up --no-deps must not create the linked dependency.
- TestStartSingleServiceAndDependency: create/start walk the dependency
chain and nothing else — now asserting the unrelated services have no
container at all, stronger than the legacy message matching.
The one-off and multi-file tests stay legacy: the vocabulary has no
one-off awareness yet and a scenario holds a single compose file.
The links and start-stop-deps fixtures become unused and are removed.
Signed-off-by: Nicolas De Loof <nicolas.deloof@gmail.com>
