Plan 87 phase C. A compose app on slots runs each slot as its own
project, <name>-a / <name>-b, rendered from the merged compose config:
container_name stripped, only the web service published, on the
slot's loopback port, and every named volume pinned to the name it has
today. Without the pin compose prefixes volumes with the project name
and slot B would start on empty ones; the real-Docker leg checks this.
Stateful services (a database, cache or queue with a named volume)
cannot run twice. They move once, on an explicit previewed split, into
a shared <name>-data project that both slots reach by the same names.
The webhook, template-update and rollback paths deploy through the
engine instead of stopping the stack. The --scale web=2 rolling
restart and the Webhook.zero_downtime flag are deleted: it assumed a
service named web, ignored its own health result, and no UI set it.
Compose slot images get immutable per-deployment tags and are pruned
with the rest.
Juan Denis
d0b11714e7
