[client] Unify peer and route ACL filtering with multi-source rules (#6322)

* Unify peer and route ACL filtering with multi-source peer rules

* Remove partial userspace firewall mode and open foreign chains via a table-less allower

* Snapshot iptables rule maps before persisting state

* Scope userspace firewall wildcard source rules per address family

* Install nftables peer filter and mangle rules in a single transaction

* Share the iptables jump rule spec between install and cleanup

* Fix legacy ACL source wildcard and keep rollback tracking on delete failure

* Fix CI: recognize multi-value port set lookups in tests and correct PeerIP lint suppression

* Fall back to per-prefix filter rules when ipset is unavailable

* Annotate legacy PeerIP usages in ACL tests and fix import formatting

* Keep firewall rule bookkeeping in step with the kernel on replace and teardown

* Release the routing reference when the route manager shuts down

* Keep set references and rule tracking consistent when a routing rule fails

client/firewall/manager/set.go

@@ -40,7 +40,7 @@ func (h Set) Comment() string {
 
 // NewPrefixSet generates a unique name for an ipset based on the given prefixes.
 func NewPrefixSet(prefixes []netip.Prefix) Set {
-	// sort for consistent naming
+	prefixes = slices.Clone(prefixes)
 	SortPrefixes(prefixes)
 
 	hash := sha256.New()