fix(ci): load default.yml inventory vars in swarm deploy step

The swarm CI deploy invoked cli.administration.deploy.swarm with only
swarm.yml and the runtime extras as -e files. Default-inventory vars
(OIDC.CLIENT.SECRET, users, design, ...) were applied only to
host_vars/<MGR>.yml via the provision step's --vars-file argument, so
they reached mgr-01 but not the workers. Workers without OIDC.CLIENT
defaults rendered roles/web-app-keycloak/templates/import/clients/default.json.j2
into "object of type 'dict' has no attribute 'SECRET'" at the realm
import step (CI run 27044129926).

Load default.yml as inventory-wide extra-vars before swarm.yml, so the
two are merged uniformly across mgr-01 and workers. swarm.yml still
overrides any keys it sets (extra-vars merge left-to-right, last wins).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

.github/workflows/test-deploy-swarm.yml

@@ -169,6 +169,7 @@ jobs:
             /tmp/inv/devices.yml \
             -p /tmp/inv/.password \
             --skip-build --skip-cleanup --skip-backup \
+            -e @inventories/development/default.yml \
             -e @inventories/development/swarm.yml \
             -e @/tmp/swarm-nfs-extras.yml