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/importer/importer_test.go

@@ -205,3 +205,15 @@ view "internal" {
 		t.Errorf("imported state has errors: %v", ps)
 	}
 }
+
+func TestWithoutViewKeys(t *testing.T) {
+	for _, tc := range []struct{ in, want []string }{
+		{[]string{"!key jarl-view-external", `key "jarl-view-internal"`, "homelab"}, []string{"homelab"}},
+		{[]string{"key jarl-view-external", "any"}, []string{}},
+		{[]string{"key xfer", "any"}, []string{"key xfer", "any"}},
+	} {
+		if got := withoutViewKeys(tc.in); strings.Join(got, ";") != strings.Join(tc.want, ";") || got == nil {
+			t.Errorf("%v: %v, want %v", tc.in, got, tc.want)
+		}
+	}
+}