Give every view a TSIG key that selects it

Each view's match-clients starts with "key jarl-view-NAME" (after
"!key" for the views listed after it), so a query signed with a view's
key lands in that view from any address. The secrets are derived from a
random seed in Jarl's database. The delegation check signs its queries
to this server's own addresses with the key of the zone's view: before,
they got whichever view matched the server's address, usually internal.
jarl view key / GET /views/{id}/key show a key for dig -k (tsig:write,
audited). jarl-view- key names are reserved; the importer drops view
keys from a configuration Jarl wrote.

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

internal/render/render.go

@@ -149,7 +149,7 @@ const headerText = "Generated by Jarl. DO NOT EDIT: changes made here are overwr
 // from jarld's configuration (e.g. for query statistics).
 func Render(s *model.State, p Paths, x Extras) *Output {
 	out := &Output{Spans: map[string][]Span{}, ZoneFiles: map[int64]string{}}
-	keys := renderKeys(s)
+	keys := renderKeys(s) + renderViewKeys(s, x)
 	out.Files = append(out.Files, &File{Path: p.KeysConfig(), Content: []byte(keys), Mode: 0o640, Kind: KindKeys, Secret: true})
 	conf, spans := renderConfig(s, p, x, out)
 	out.Files = append(out.Files, &File{Path: p.MainConfig(), Content: []byte(conf), Mode: 0o640, Kind: KindConfig})
@@ -350,8 +350,8 @@ func renderConfig(s *model.State, p Paths, x Extras, out *Output) (string, []Spa
 			w.write(commentBlock("//", v.Comment))
 		}
 		w.write(fmt.Sprintf("view %s {\n", namedconf.QuoteString(v.Name)))
-		if len(v.MatchClients) > 0 {
-			writeAML(w, "match-clients", v.MatchClients)
+		if mc := viewMatchClients(s, x, v); len(mc) > 0 {
+			writeAML(w, "match-clients", mc)
 		}
 		if len(v.MatchDestinations) > 0 {
 			writeAML(w, "match-destinations", v.MatchDestinations)