CLI: don't print "and N more" when the server sends no PTR list

A 0.6.1-rc.2 server sends ptr_other_views without ptr_other_views_list,
so zone show printed only "and 1 more" under "Other views:".

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

cmd/jarl/ptrfills_test.go

@@ -0,0 +1,25 @@
+package main
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+
+	"jarl/internal/api"
+)
+
+func TestPrintPTRFills(t *testing.T) {
+	var b bytes.Buffer
+	printPTRFills(&b, []api.PTRFill{{Address: "10.0.10.20", Target: "nextcloud.adbraun.lol.", From: "internal"}}, 3)
+	out := b.String()
+	if !strings.Contains(out, "10.0.10.20 -> nextcloud.adbraun.lol (view internal)") || !strings.Contains(out, "and 2 more") {
+		t.Errorf("listed fills:\n%s", out)
+	}
+
+	// An older server sends the count without the list.
+	b.Reset()
+	printPTRFills(&b, nil, 1)
+	if b.Len() != 0 {
+		t.Errorf("no list from the server printed %q, want nothing", b.String())
+	}
+}

cmd/jarl/zones.go

@@ -1183,8 +1183,13 @@ func terminalWidth() int {
 }
 
 // printPTRFills lists PTR records a reverse zone lacks under zone show's
-// line about them: address -> name, and the view the name is from.
+// line about them: address -> name, and the view the name is from. A server
+// older than the CLI may send the count without the list; then nothing is
+// listed, rather than "and N more" under no addresses.
 func printPTRFills(w io.Writer, fills []api.PTRFill, total int) {
+	if len(fills) == 0 {
+		return
+	}
 	for _, f := range fills {
 		from := ""
 		if f.From != "" {