- lib.common.revert_to_applied(): restore a config file from its
_last_applied_config snapshot (stamped hash); no baseline -> skip with
reason, file untouched
- firewall config_apply now stamps the applied baseline like the other
subsystems; GET /firewall/config and the state collector strip the
internal _last_applied_* keys
- POST /status/cancel-all + /api/status/cancel-all: revert pending
subsystems, {cancelled, skipped, errors}, partial-failure safe
- dashboard: "Cancel All Changes" button with confirm modal
(CancelConfirm, reuses the pending-changes modal rows); the pending
changes card is hidden entirely when nothing is pending
- tests: revert_to_applied, status_cancel_all, firewall stamping/meta
stripping, /api/status/cancel-all route, node tests for CancelConfirm;
firewall _config_apply tests no longer write the real repo config
- docs: api.md, state-model.md, config.md, hoover.md
