Disable records instead of deleting them

A disabled record stays in Jarl with its ID, TTL and comment but is
left out of the zone; the zone file lists it as a comment. Web UI
toggle, jarl record disable|enable, record.disable|enable operations
and API endpoints. Database schema 5.

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

internal/engine/diffops.go

@@ -88,7 +88,7 @@ func DiffOps(from, to *model.State) []model.Op {
 	}
 	for _, k := range sortedKeys(to.Records) {
 		n := to.Records[k]
-		in := RecordInput{ZoneID: n.ZoneID, Name: &n.Name, Type: &n.Type, Data: &n.Data, Comment: &n.Comment}
+		in := RecordInput{ZoneID: n.ZoneID, Name: &n.Name, Type: &n.Type, Data: &n.Data, Comment: &n.Comment, Disabled: &n.Disabled}
 		if n.TTL != nil {
 			in.TTL = model.Some(*n.TTL)
 		} else {