Start a never-judged head's check before the re-judges a trunk move asks, oldest first (issue 1897 S1)

A new pull request waited 25 to 45 minutes behind every open pull request's re-judge after a
merge. The semaphore becomes a ranked admission (ADR 0536 §4); checker_status names the
waiting checks by kind.

modules/mesh-delivery-checker/cmd/mesh-delivery-checker-tools/main.go

@@ -145,7 +145,8 @@ func Tools(r check.Reader) []stdio.Tool {
 		{Name: check.StatusReadTool,
 			Description: "What holds the checker back and what runs: the capacity per node (the setting, the default one step per node), whether the controller's " +
 				"delivery plans in their build phase hold a key (no new check starts while one does), the steps in flight on the build modules by node, and the " +
-				"candidates without a verdict for their heads (a group of hq's pull requests alone is left out: merge-check.sh judges it). A key a build " +
+				"candidates without a verdict for their heads (a group of hq's pull requests alone is left out: merge-check.sh judges it), and the " +
+				"candidates whose check waits by kind (waiting_by_kind: new, nodes, and trunk, which start after the other two). A key a build " +
 				"module left running (started past the step bound, or its build module not running on its node) is listed apart under left_running " +
 				"with why, and not counted. The places the checker holds are in its process, not in a bucket, and the answer says so. Read-only.",
 			Input: map[string]any{"type": "object", "properties": map[string]any{}},
@@ -184,19 +185,21 @@ func main() {
 		Capacity:   capacity, HaveState: read(stdio.State("node-engine.have")), StepBound: stepBound()}
 	tries := stdio.State(check.TriesState)
 	source := stdio.State("mesh-delivery-gate.source")
+	trunks := func() (map[string]string, error) {
+		e, err := source.Get(delivery.SourceMainKey)
+		if err != nil || e == nil {
+			return nil, err
+		}
+		s, err := delivery.DecodeSource(e.Value)
+		return s.Heads, err
+	}
+	r.Trunks = trunks
 	trying := Trying{
 		Tries: stateStore{StateRead: read(tries), create: func(key string, value []byte) error {
 			_, err := tries.Create(key, json.RawMessage(value))
 			return err
 		}},
-		Trunks: func() (map[string]string, error) {
-			e, err := source.Get(delivery.SourceMainKey)
-			if err != nil || e == nil {
-				return nil, err
-			}
-			s, err := delivery.DecodeSource(e.Value)
-			return s.Heads, err
-		},
+		Trunks: trunks,
 	}
 	if err := stdio.Serve("", append(Tools(r), TryTools(trying)...)); err != nil {
 		fmt.Fprintf(os.Stderr, "[mesh-delivery-checker-tools] %v\n", err)