Different blocking for different devices: steps and client groups

Client groups put devices (addresses, networks, or ACLs of them) at a
blocking step: off (only your rules), normal (the default), or steps
added above it, each including the lists of the steps below. Lists
start at a step. In each view, a gate policy zone in front of a step's
lists lets the devices below that step through (rpz-client-ip triggers
with rpz-passthru), so every list is still loaded once. The IPv6 part
of a gate leaves the IPv4-mapped range out: named matches IPv4 clients
as ::ffff:a.b.c.d.

Web UI: a Devices panel on the Blocking page and a step on each list.
CLI: jarl block step, jarl block group, jarl blocklist --step. API:
/blocking/steps, /blocking/groups. Database schema 8.

Also: copying the state kept empty lists as empty (not nil), so
reverting a changeset no longer adds restore operations for unchanged
blocklists, rules and views.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/engine/diffops.go

@@ -104,9 +104,19 @@ func DiffOps(from, to *model.State) []model.Op {
 			add(OpRecordUpdate, k, o.Version, in, fmt.Sprintf("restore %s %s %s", n.Name, n.Type, n.Data))
 		}
 	}
+	// Steps before the lists and groups that use them.
+	for _, k := range sortedKeys(to.BlockSteps) {
+		n := to.BlockSteps[k]
+		in := BlockStepInput{Name: &n.Name, Position: model.Ptr(n.Position), Comment: &n.Comment}
+		if o, ok := from.BlockSteps[k]; !ok {
+			add(OpBlockStepCreate, k, 0, in, "add blocking step "+n.Name)
+		} else if !sameObject(o, n) {
+			add(OpBlockStepUpdate, k, o.Version, in, "restore blocking step "+n.Name)
+		}
+	}
 	for _, k := range sortedKeys(to.Blocklists) {
 		n := to.Blocklists[k]
-		in := BlocklistInput{Name: &n.Name, URL: &n.URL, ViewIDs: model.Ptr(append([]int64{}, n.ViewIDs...)), Disabled: &n.Disabled, Comment: &n.Comment}
+		in := BlocklistInput{Name: &n.Name, URL: &n.URL, ViewIDs: model.Ptr(append([]int64{}, n.ViewIDs...)), Disabled: &n.Disabled, Comment: &n.Comment, StepID: model.Ptr(n.StepID)}
 		if o, ok := from.Blocklists[k]; !ok {
 			add(OpBlocklistCreate, k, 0, in, "add blocklist "+n.Name)
 		} else if !sameObject(o, n) {
@@ -122,7 +132,21 @@ func DiffOps(from, to *model.State) []model.Op {
 			add(OpBlockRuleUpdate, k, o.Version, in, "restore rule: "+ruleLabel(n))
 		}
 	}
+	for _, k := range sortedKeys(to.ClientGroups) {
+		n := to.ClientGroups[k]
+		in := ClientGroupInput{Name: &n.Name, Members: model.Ptr(append([]string{}, n.Members...)), StepID: model.Ptr(n.StepID), ViewIDs: model.Ptr(append([]int64{}, n.ViewIDs...)), Comment: &n.Comment}
+		if o, ok := from.ClientGroups[k]; !ok {
+			add(OpClientGroupCreate, k, 0, in, "add client group "+n.Name)
+		} else if !sameObject(o, n) {
+			add(OpClientGroupUpdate, k, o.Version, in, "restore client group "+n.Name)
+		}
+	}
 	// Deletions, most dependent objects first.
+	for _, k := range sortedKeys(from.ClientGroups) {
+		if _, ok := to.ClientGroups[k]; !ok {
+			add(OpClientGroupDelete, k, from.ClientGroups[k].Version, nil, "delete client group "+from.ClientGroups[k].Name)
+		}
+	}
 	for _, k := range sortedKeys(from.BlockRules) {
 		if _, ok := to.BlockRules[k]; !ok {
 			add(OpBlockRuleDelete, k, from.BlockRules[k].Version, nil, "delete rule: "+ruleLabel(from.BlockRules[k]))
@@ -133,6 +157,11 @@ func DiffOps(from, to *model.State) []model.Op {
 			add(OpBlocklistDelete, k, from.Blocklists[k].Version, nil, "delete blocklist "+from.Blocklists[k].Name)
 		}
 	}
+	for _, k := range sortedKeys(from.BlockSteps) {
+		if _, ok := to.BlockSteps[k]; !ok {
+			add(OpBlockStepDelete, k, from.BlockSteps[k].Version, nil, "delete blocking step "+from.BlockSteps[k].Name)
+		}
+	}
 	for _, k := range sortedKeys(from.Records) {
 		if _, ok := to.Records[k]; !ok {
 			o := from.Records[k]