test(core): make test sentinels effective

packages/core/test/shared-schema.test.ts

@@ -162,7 +162,6 @@ test("Core reuses the canonical shared schemas", async () => {
   ]
   for (const [core, shared] of schemas) expect(core).toBe(shared)
 
-  expect(Agent.Info.default(Agent.ID.make("test"))).toEqual(Agent.Info.default(Agent.ID.make("test")))
   expect(coreModel.Info.default(coreProvider.ID.make("test"), coreModel.ID.make("model"))).toEqual(
     Model.Info.default(Provider.ID.make("test"), Model.ID.make("model")),
   )

packages/core/test/skill.test.ts

@@ -45,7 +45,9 @@ describe("Skill", () => {
           value.description = "Updated"
           value.id = Skill.ID.make("ignored")
         })
-        draft.update("missing", () => Effect.die("unreachable"))
+        draft.update("missing", () => {
+          throw new Error("unreachable")
+        })
         draft.add(info("deploy", "Deploy"))
         draft.remove("deploy")
       })