Say a channel's failure, its standing, and what a message replies to

go/asks/asks.go

@@ -308,6 +308,8 @@ type Message struct {
 	Buttons []Button `json:"buttons,omitempty"`
 	Urgent  bool     `json:"urgent,omitempty"`
 	Silent  bool     `json:"silent,omitempty"`
+	// Reply is the Choice or LinkAsked this answers, by its ID: the channel shows it where that was made.
+	Reply string `json:"reply,omitempty"`
 }
 
 // Sender is who a channel's service says sent something: the account, the name it shows, and whether the
@@ -318,6 +320,29 @@ type Sender struct {
 	Authenticated bool   `json:"authenticated"`
 }
 
+// Failed is a message a channel could not deliver: its handle, why, and whether trying again could help.
+type Failed struct {
+	Handle    string    `json:"handle"`
+	Why       string    `json:"why"`
+	Permanent bool      `json:"permanent,omitempty"`
+	At        time.Time `json:"at"`
+}
+
+// Standing is what a channel says of itself, at least every five minutes and whenever it changes:
+// whether it can send now, why not, and whether its edits notify nobody.
+type Standing struct {
+	Ready         bool      `json:"ready"`
+	Why           string    `json:"why,omitempty"`
+	EditsSilently bool      `json:"edits-silently,omitempty"`
+	At            time.Time `json:"at"`
+}
+
+// What a channel says of its own delivery, on IntakeSubject.
+const (
+	FailedWhat   = "failed"
+	StandingWhat = "standing"
+)
+
 // Choice is a button chosen on a channel.
 type Choice struct {
 	// ID is the channel's own for this arrival, unique, so the router acts on it once.