Make delivery and integration failures explicit

Persist reminder presentations and retry state, atomically complete collapsed deliveries, fall back across away reaches, and block permanent failures visibly (V-715, V-678). Fail closed when enabled integrations lack credentials and keep remote arms explicitly dark (V-691). Give mavweb one sanitized, request-correlated error contract (V-689). Owner explicitly requested direct commits to master.

internal/ipc/storeapi.go

@@ -149,7 +149,7 @@ func (a *storeAPI) DeliveryAttempts(ctx context.Context, status string, n int) (
 	return mapRows(as, err, func(at store.DeliveryAttempt) DeliveryAttempt {
 		out := DeliveryAttempt{
 			ID: at.ID, Kind: at.Kind, Rule: at.Rule, ReminderID: at.ReminderID,
-			Channel: at.Channel, Status: at.Status, Created: at.Created,
+			DeliveryGroup: at.DeliveryGroup, Channel: at.Channel, Status: at.Status, Created: at.Created,
 		}
 		if at.HasComplete {
 			t := at.Completed
@@ -352,13 +352,18 @@ func toTool(t store.Tool) Tool {
 
 func toReminder(r store.Reminder) Reminder {
 	return Reminder{
-		ID:         r.ID,
-		CreatedTs:  r.CreatedTs,
-		FireTs:     r.FireTs,
-		NextFireTs: r.NextFireTs,
-		Payload:    r.Payload,
-		Status:     r.Status,
-		Cron:       r.Cron,
+		ID:                   r.ID,
+		CreatedTs:            r.CreatedTs,
+		FireTs:               r.FireTs,
+		NextFireTs:           r.NextFireTs,
+		Payload:              r.Payload,
+		Status:               r.Status,
+		Cron:                 r.Cron,
+		DeliveryGroup:        r.DeliveryGroup,
+		DeliveryAttempts:     r.DeliveryAttempts,
+		NextAttemptTs:        r.NextAttemptTs,
+		DeliveryBlockedTs:    r.DeliveryBlockedTs,
+		DeliveryBlockedError: r.DeliveryBlockedError,
 	}
 }