Keep built-ins and policies out of the busiest rules

The established built-in passes most of the traffic, so it topped the
statistics' busiest rules every time and made every rule's bar look
empty. The summary now lists rules and NAT objects in rules, and
built-ins and policies in builtins; the Statistics page and hc stats
show them as two lists.

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

internal/stats/query.go

@@ -191,8 +191,11 @@ type Summary struct {
 	// chain.
 	Drops        int64   `json:"drops"`
 	DropsByChain []Entry `json:"drops_by_chain"`
-	// Rules are the busiest rules, built-ins and policies, by packets.
-	Rules []Entry `json:"rules"`
+	// Rules are the busiest rules and NAT objects, by packets; BuiltIns
+	// the busiest built-ins and policies, kept apart because the
+	// established built-in counts most of the traffic.
+	Rules    []Entry `json:"rules"`
+	BuiltIns []Entry `json:"builtins"`
 	// Connections: the most tracked at once (per-bucket averages), and
 	// the table's size.
 	PeakConnections int64   `json:"peak_connections"`
@@ -251,9 +254,15 @@ func (q *Querier) Summary(ctx context.Context, since time.Duration, topLimit int
 	s.Zones, s.Interfaces = traffic("zrx:", "ztx:"), traffic("rx:", "tx:")
 	s.Drops = all["drops"]
 	s.DropsByChain = sorted(all, "drop:")
-	s.Rules = sorted(all, "hits:")
-	if len(s.Rules) > topLimit {
-		s.Rules = s.Rules[:topLimit]
+	s.Rules, s.BuiltIns = []Entry{}, []Entry{}
+	for _, e := range sorted(all, "hits:") {
+		if strings.HasPrefix(e.Key, "b-") || strings.HasPrefix(e.Key, "p-") {
+			if len(s.BuiltIns) < topLimit {
+				s.BuiltIns = append(s.BuiltIns, e)
+			}
+		} else if len(s.Rules) < topLimit {
+			s.Rules = append(s.Rules, e)
+		}
 	}
 	if tl, err := q.Timeline(ctx, since, "auto", []string{"g:" + GaugeConntrack, "g:" + GaugeConntrackMax}); err == nil {
 		for _, v := range tl.Series[0].Values {