Mark signed zones with a padlock, and name clients in statistics

The zones list shows a padlock after signed zones, linking to their
DNSSEC tab. Client lists in the statistics show the host name Jarl's
records have for each address (PTR, else A/AAAA); no DNS queries.

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

internal/stats/collector.go

@@ -528,7 +528,7 @@ func (c *Collector) updateWarnings() {
 func top(m map[string]int64, n int) []Entry {
 	out := make([]Entry, 0, len(m))
 	for k, v := range m {
-		out = append(out, Entry{k, v})
+		out = append(out, Entry{Key: k, Count: v})
 	}
 	slices.SortFunc(out, func(a, b Entry) int {
 		if a.Count != b.Count {