Let delivery-stop leave merges out and walk the others again, so a group stop ends only its own change (hq issue 459, ADR 0299)

One walk carries every merge of its batch, so ending it for one group member
ended every other delivery on it. delivery-stop now takes without: the walk
ends, every other merge it answered is batched again, and each later merge of
a left-out merge's repository is left out too, since it contains it.

internal/inventory/plans.go

@@ -187,6 +187,11 @@ type PlanDelivery struct {
 	// TakenOverBy names the walk a walk folded before it started was taken over by: its merges are that
 	// walk's now.
 	TakenOverBy string `json:"taken_over_by,omitempty"`
+	// WalkedAgainBy names, on a walk stopped without some of its merges, the batch that walks its other merges
+	// again, and LeftOut the merges it left out (novox/hq issue 459, ADR 0299): a delivery of a merge left out
+	// ends stopped with the walk, one of a merge walked again follows that batch's walk.
+	WalkedAgainBy string        `json:"walked_again_by,omitempty"`
+	LeftOut       []PlanLeftOut `json:"left_out,omitempty"`
 	// Batch is the window of a batch; nil once it is cut into a walk.
 	Batch *PlanBatch `json:"batch,omitempty"`
 	// Alone says the walk walks one merge on its own commit, after a failed walk carried it in a later one:
@@ -194,6 +199,16 @@ type PlanDelivery struct {
 	Alone bool `json:"alone,omitempty"`
 }
 
+// PlanLeftOut is a merge a stop left out of the batch that walks a stopped walk's merges again (novox/hq ADR
+// 0299): a merge stopped, or a later merge of its repository's branch, which contains the stopped one and so
+// cannot be walked without delivering it.
+type PlanLeftOut struct {
+	Repository string `json:"repository"`
+	Commit     string `json:"commit"`
+	// Contains is the stopped merge a later merge contains; empty for a merge stopped itself.
+	Contains string `json:"contains,omitempty"`
+}
+
 // Waiting is whether the walk waits for its delivery's word.
 func (p Plan) Waiting() bool {
 	return p.Delivery != nil && p.Delivery.Awaits != "" && p.Delivery.Go == nil