Fix nftables direct-mode operations so create, edit, delete, and move actions apply only the selected table instead of rewriting or applying the full ruleset. This avoids copying firewalld-owned rules, or any other externally managed rules, into Webmin’s save file and prevents operations from failing against externally managed tables. Also remove previously added unsafe full-ruleset flush action and keep Apply Configuration out of direct mode (will be further reworked).
