fix: remove OMP manager startup ordering cycle with nano #40

Remove the unnecessary omp-manager.service After=nano.service edge. nano.service starts after multi-user.target, while omp-manager is wanted by and implicitly ordered before that target; the added edge closed the reported cycle and systemd dropped the manager start job. Yield notifications already retry, so nano is not a startup dependency. Preserve the seed, Docker and task-image ordering. Homura full toplevel derivation evaluation passes; evaluated service dependencies confirm the nano edge is gone and all three real prerequisites remain. Not deployed by this PR.