node-engine: the verbs seat-list and seat-list-again (the operator and the healers) and the state findings, with fixtures (ADR 0636 §1, §7; issue 1966)

seats/node-engine/fixtures/states.json

@@ -0,0 +1,17 @@
+[
+  {
+    "name": "the finding of a seat list unread, as the engine writes it",
+    "of": "state:findings/<key>",
+    "given": {
+      "v": 1,
+      "key": "machine.ace.seat-list-unread",
+      "kind": "seat-list-unread",
+      "subject": {"scope": "machine", "id": "ace", "machine": "ace"},
+      "severity": "warning",
+      "summary": "the seat list has not been read for five minutes",
+      "source": "node-engine.seat-list",
+      "observer": "mesh-host",
+      "at": "2026-11-05T14:00:00Z"
+    }
+  }
+]

seats/node-engine/fixtures/verbs.json

@@ -72,5 +72,50 @@
         }
       ]
     }
+  },
+  {
+    "name": "seat-list answers what the engine holds and what it waits for",
+    "of": "verb:seat-list.answer",
+    "given": {
+      "status": {
+        "heard": false,
+        "held": [
+          {
+            "seat": "node-engine",
+            "source": "bootstrap"
+          },
+          {
+            "seat": "node-files",
+            "source": "trunk",
+            "digest": "3f2a9c"
+          }
+        ],
+        "waiting": [
+          "node-engine"
+        ],
+        "last-error": "no answer"
+      },
+      "health": "the seat list is held from the bootstrap and nothing new is acted on"
+    }
+  },
+  {
+    "name": "seat-list-again answers the error when the read failed",
+    "of": "verb:seat-list-again.answer",
+    "given": {
+      "status": {
+        "heard": false,
+        "held": [
+          {
+            "seat": "node-engine",
+            "source": "bootstrap"
+          }
+        ],
+        "waiting": [
+          "node-engine"
+        ]
+      },
+      "health": "the seat list is held from the bootstrap",
+      "error": "seatlist: no answer"
+    }
   }
 ]