Disable records instead of deleting them

A disabled record stays in Jarl with its ID, TTL and comment but is
left out of the zone; the zone file lists it as a comment. Web UI
toggle, jarl record disable|enable, record.disable|enable operations
and API endpoints. Database schema 5.

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

internal/engine/inputs.go

@@ -29,6 +29,12 @@ const (
 	OpOptionUpdate   = "option.update"
 	OpOptionDelete   = "option.delete"
 	OpSettingsUpdate = "settings.update"
+
+	// Requests only: disabling and enabling records, by ID or by match
+	// (zone, name, type and optionally data), become record.update
+	// operations.
+	OpRecordDisable = "record.disable"
+	OpRecordEnable  = "record.enable"
 )
 
 // OpKinds lists all operation kinds.
@@ -121,8 +127,10 @@ type RecordInput struct {
 	TTL     model.Opt[uint32] `json:"ttl,omitzero"` // null: use the zone default
 	Data    *string           `json:"data,omitempty"`
 	Comment *string           `json:"comment,omitempty"`
-	// PTR also creates (or deletes) the matching PTR record in the
-	// reverse zone, for A and AAAA records.
+	// Disabled keeps the record in Jarl but out of the zone.
+	Disabled *bool `json:"disabled,omitempty"`
+	// PTR also creates (or deletes, disables or enables) the matching PTR
+	// record in the reverse zone, for A and AAAA records.
 	PTR bool `json:"ptr,omitempty"`
 	// MissingOK makes a delete-by-match succeed when nothing matches.
 	MissingOK bool `json:"missing_ok,omitempty"`