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/engine/inputs.go

@@ -51,8 +51,21 @@ const (
 	// operations.
 	OpRecordDisable = "record.disable"
 	OpRecordEnable  = "record.enable"
+	// Acknowledging an exposure finding (docs/exposure.md), and taking it
+	// back, become view.update or settings.update operations.
+	OpExposureAck   = "exposure.ack"
+	OpExposureUnack = "exposure.unack"
 )
 
+// AckInput acknowledges (or un-acknowledges) an exposure finding of a view
+// (by ID or name), or of the server (neither given).
+type AckInput struct {
+	ViewID int64  `json:"view_id,omitempty"`
+	View   string `json:"view,omitempty"`
+	Code   string `json:"code"`
+	Reason string `json:"reason,omitempty"`
+}
+
 // OpKinds lists all operation kinds.
 var OpKinds = []string{OpZoneCreate, OpZoneUpdate, OpZoneDelete, OpRecordCreate, OpRecordUpdate, OpRecordDelete, OpRRSetReplace,
 	OpViewCreate, OpViewUpdate, OpViewDelete, OpViewReorder, OpACLCreate, OpACLUpdate, OpACLDelete,
@@ -184,6 +197,9 @@ type ViewInput struct {
 	AdoptZones bool `json:"adopt_zones,omitempty"`
 	// Cascade (delete) also deletes the view's zones.
 	Cascade bool `json:"cascade,omitempty"`
+	// Exposure is "auto" (or ""), "public" or "private" (docs/exposure.md).
+	Exposure     *string                  `json:"exposure,omitempty"`
+	Acknowledged *[]model.Acknowledgement `json:"acknowledged,omitempty"`
 }
 
 // ReorderInput sets the order of views.
@@ -227,6 +243,9 @@ type SettingsInput struct {
 	Expire       *uint32   `json:"expire,omitempty"`
 	NegativeTTL  *uint32   `json:"negative_ttl,omitempty"`
 	SerialPolicy *string   `json:"serial_policy,omitempty"`
+	// Exposure and Acknowledged are the server's (docs/exposure.md).
+	Exposure     *string                  `json:"exposure,omitempty"`
+	Acknowledged *[]model.Acknowledgement `json:"acknowledged,omitempty"`
 }
 
 // DeleteInput carries options for delete operations.