fix(ci): add full docker PATH in SSH pre-flight and deploy commands

The NAS 'admin' user has docker at
/share/CACHEDEV1_DATA/.qpkg/container-station/usr/bin/docker which
isn't in the default PATH for non-interactive SSH. Set the PATH
explicitly in both the pre-flight check and the actual deploy.

.gitea/workflows/ci-cd.yaml

@@ -87,7 +87,8 @@ jobs:
           NAS_SSH_HOST="${NAS_HOST%%:*}"
           echo "Using NAS_SSH_HOST=$NAS_SSH_HOST NAS_SSH_PORT=$NAS_SSH_PORT"
           ssh -o StrictHostKeyChecking=no -o ConnectTimeout=5 -p "$NAS_SSH_PORT" \
-              "$NAS_USER@$NAS_SSH_HOST" 'hostname && docker version --format "{{.Server.Version}}"' \
+              "$NAS_USER@$NAS_SSH_HOST" \
+              'export PATH=/share/CACHEDEV1_DATA/.qpkg/container-station/usr/bin:$PATH; hostname && docker version --format "{{.Server.Version}}"' \
               | head
 
           echo "--- Reading docker-compose.prod.yml from the repo ---"