Internet exposure checks and response rate limiting

Jarl works out which views are reachable from the internet (match-clients
ending in a catch-all, not private-looking addresses: an internal view of a
global IPv6 prefix is still yours; a server without views: open allow-query
and a non-private listen address), with a per-view override (schema 9), and
checks public ones: rate limiting, open resolver, minimal-any, cache
snooping, open NOTIFY and transfers, version and host name, management
interfaces. Fixes are staged like any change, including rate limiting from
ISC's example in log-only mode with the secondaries exempt, then enforcing.
named logs what rate limiting limits (or would, in log-only mode, where its
counters don't move) as query-errors; Jarl routes those lines to its log
and counts them (rrl breakdown, ratelimited top lists, Prometheus
jarl_ratelimit_logged_total), shown on the new Exposure page.

A change that newly opens a public view up must be confirmed (accept_risk,
--accept-risk, a checkbox on the Changes page; 409 confirm_risk
otherwise). Findings can be acknowledged with a reason and stay visible as
info. GET /exposure, POST /exposure/fix|ack|unack, jarl exposure,
docs/exposure.md.

Also fixes query statistics skipping TSIG-signed queries ("IP#port/key
NAME" in named's log).

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

internal/render/stats.go

@@ -72,9 +72,10 @@ func (h *StatsHooks) statsStatement(user *model.Option) string {
 }
 
 // loggingStatement returns the logging statement with Jarl's channel and
-// the responses category (and rpz, for blocking's rewrites), merged into
-// the user's own if there is one.
-func (h *StatsHooks) loggingStatement(user *model.Option, rpz bool) string {
+// the responses category (rpz too, for blocking's rewrites, and
+// query-errors for rate limiting), merged into the user's own if there is
+// one.
+func (h *StatsHooks) loggingStatement(user *model.Option, rpz, rrl bool) string {
 	var st *namedconf.Stmt
 	if user != nil {
 		var err error
@@ -92,6 +93,9 @@ func (h *StatsHooks) loggingStatement(user *model.Option, rpz bool) string {
 	if rpz {
 		categories = append(categories, "rpz")
 	}
+	if rrl {
+		categories = append(categories, "query-errors")
+	}
 	for _, cat := range categories {
 		merged := false
 		for _, s := range b.Stmts {
@@ -101,7 +105,13 @@ func (h *StatsHooks) loggingStatement(user *model.Option, rpz bool) string {
 			}
 		}
 		if !merged {
-			b.Stmts = append(b.Stmts, namedconf.NewStmt("category", cat, namedconf.NewBlock(namedconf.NewStmt(StatsChannelName))))
+			channels := namedconf.NewBlock(namedconf.NewStmt(StatsChannelName))
+			if cat == "query-errors" {
+				// Naming the category takes it away from named's
+				// default destination: keep that too.
+				channels.Stmts = append(channels.Stmts, namedconf.NewStmt("default_syslog"))
+			}
+			b.Stmts = append(b.Stmts, namedconf.NewStmt("category", cat, channels))
 		}
 	}
 	prefix := ""