fix(setup): recognize persisted re-run + add prior-run preface and --force flag
step_journal previously ignored the persisted-config match before checking whether a journal was non-empty, so non-interactive re-runs against an already configured journal dead-ended unnecessarily. Setup now summarizes the prior manifest state at the top of run_setup for clean, partial, or absent prior runs. The new --force flag only changes the clean-rerun preface wording today and does not change step execution behavior; tests/test_setup.py adds seven focused tests for the rerun and preface cases.