Add a way to stop docker after e2e tests if it wasn't already running.

README.md

@@ -70,7 +70,8 @@ SKIP_E2E=1 bun run ci:check
 ```
 
 `bun test:e2e` starts the isolated local stack and currently performs generic
-stack smoke checks. It skips in CI and when `SKIP_E2E=1` is set.
+stack smoke checks. It stops the stack afterward only when the stack was not
+already running. It skips in CI and when `SKIP_E2E=1` is set.
 
 Shared dependency versions belong in root catalogs. Edit the root catalog, run
 `bun install`, then `bun lint:ws`; do not run `bun update` inside a workspace.