Fix zone list filtering and BIND warning display; add a views guide

- jarl zone list showed only primary zones. zone create binds its --type
  flag (default "primary") to the same variable as list's --type, so the
  default leaked into the list filter and hid hint, secondary and forward
  zones. list now has its own variable. TestListQueries runs list
  commands against a fake server and checks the filters they send.
- named-checkconf/named-checkzone messages are classified by the tool's
  exit code: on success, everything printed is a warning. Warnings such
  as 'both "recursion no;" and "allow-recursion" active' were shown as
  errors. The CLI, jarld check and the web UI now label them as warnings
  and skip the routine "loaded serial" lines.
- The zone_outside_view error points at --adopt-zones.
- docs/views.md: step-by-step split DNS for a server that has no views
  yet, tested on a copy of a stock Ubuntu 26.04 setup. Linked from the
  README, concepts and validation docs.

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

cmd/jarld/admin.go

@@ -88,13 +88,18 @@ func printResult(res *engine.Result) {
 		printProblems(res.Problems)
 	}
 	for _, m := range res.Check {
-		if m.Error {
-			obj := ""
-			if m.Object != "" {
-				obj = " [" + m.Object + "]"
-			}
-			fmt.Printf("  named-checkconf: %s%s\n", m.Text, obj)
+		if !m.Error && (strings.HasPrefix(m.Text, "loaded serial") || m.Text == "OK") {
+			continue
 		}
+		obj := ""
+		if m.Object != "" {
+			obj = " [" + m.Object + "]"
+		}
+		label := "named-checkconf"
+		if !m.Error {
+			label += " warning"
+		}
+		fmt.Printf("  %s: %s%s\n", label, m.Text, obj)
 	}
 	for _, w := range res.Warnings {
 		fmt.Println("warning:", w)