Serve a seat's verbs from the membership once one is issued (novox/hq issue 218)

The runtime added every seat its start-up credential claims even after the mesh issued a
membership without it. A seat held once for the mesh is claimed on every machine running the
module, so ace's postgres announced the store seat the bus then refused it on.

node-tools/test/membership.test.ts

@@ -140,6 +140,36 @@ test("a seat's verbs are implemented under the seat's name, served where issued,
   }
 });
 
+// novox/hq issue 218: the store seat is claimed by every machine running postgres and held by one.
+// Where the mesh issued a membership without the seat, the claim in the credential serves nothing:
+// the module's own tools answer, the seat's verbs do not, and the runtime does not announce them.
+test("a claimant the membership does not make the holder serves none of the seat's verbs", async (t) => {
+  if (!url) return t.skip("MESH_TEST_NATS unset");
+  resetTools();
+  const stream = await anAssignmentsStream();
+  await stream.issue({
+    node: "elsewhere",
+    module: "postgres",
+    serves: [{ subject: "mesh.mod.postgres.tool.{tool}.elsewhere" }],
+    emits: "mesh.mod.postgres.event.{event}",
+    tools: "mesh.mod.postgres.tool.tools",
+  });
+  const credential = { url, node: "elsewhere", module: "postgres", claims: [{ seat: "mesh-store", scope: "mesh", serves: ["databases", "query"] }] };
+  const pg = await connectNats(credential);
+  const asker = await connectNats({ url, module: "console", node: "workstation" });
+  let stop = () => {};
+  try {
+    stop = await runTools({ broker: pg, credential, moduleEntrypoints: [fixture("store-claimant.mjs")] });
+    assert.deepEqual((await callTool(asker, "postgres.databases@elsewhere", {})).result, { software: "postgres" });
+    await assert.rejects(callTool(asker, "seat:mesh-store.databases", {}), /no responders|503/i, "the store is not held here");
+  } finally {
+    stop();
+    await asker.close();
+    await pg.close();
+    await stream.close();
+  }
+});
+
 test("a module named like its seat registers once, and answers as the module and as the seat", async (t) => {
   if (!url) return t.skip("MESH_TEST_NATS unset");
   resetTools();