fix: pin --project-directory in bin/stack.sh for correct satellite mount paths

docker-compose.observability.yml's (and every other satellite file's)
bind mounts are written relative to the repository root, matching
docker-compose.dev.yml's own convention -- but Compose otherwise derives
the project directory from whichever -f file is listed first, which
happens to already be docker-compose.dev.yml here. Pin
--project-directory . explicitly instead of relying on that ordering,
so it keeps resolving correctly regardless of what -f flags get added
or reordered later.

Author: swrichards

bin/stack.sh

@@ -36,8 +36,14 @@ cd "$REPO_ROOT"
 # satellite files use paths relative to the repository root instead, which
 # works fine alongside `include:` since they're passed as plain `-f` files.
 # See docker-compose.dev.yml's header comment for the full reasoning.
+#
+# `--project-directory .` pins that repository-root resolution explicitly,
+# rather than relying on `docker-compose.dev.yml` happening to be the first
+# `-f` file (Compose otherwise derives the project directory from whichever
+# file is listed first).
 COMPOSE=(
     docker compose
+    --project-directory .
     -f docker-compose.dev.yml
     -f docker/docker-compose.open-zaak.yml
     -f docker/docker-compose.objects-apis.yml