perf(test): avoid embedded runtime imports in btw suite

src/agents/btw.test.ts

@@ -44,6 +44,7 @@ const diagDebugMock = vi.fn();
 const ensureSelectedAgentHarnessPluginMock = vi.fn();
 const createAgentHarnessHostCapabilitiesMock = vi.fn();
 const loadTranscriptEventsMock = vi.fn();
+const builtInOpenClawHarnesses = new WeakSet<object>();
 const shouldPreferExplicitConfigApiKeyAuthMock = vi.fn((..._args: unknown[]) => false);
 const hasUsableCustomProviderApiKeyMock = vi.fn((..._args: unknown[]) => false);
 const resolveProviderEntryApiKeyProfileReferenceMock = vi.fn((_params?: unknown): unknown => ({
@@ -204,17 +205,27 @@ vi.mock("./harness/runtime-plugin.js", () => ({
     ensureSelectedAgentHarnessPluginMock(...args),
 }));
 
-vi.mock("./harness/host-capability.js", async () => {
-  const actual = await vi.importActual<typeof import("./harness/host-capability.js")>(
-    "./harness/host-capability.js",
-  );
+// Selection and host-capability owner suites execute the embedded runner and capability surface.
+// BTW only needs their identities while it verifies side-question orchestration.
+vi.mock("./harness/builtin-openclaw.js", () => ({
+  createOpenClawAgentHarness: (): AgentHarness => {
+    const harness: AgentHarness = {
+      id: "openclaw",
+      label: "OpenClaw embedded agent",
+      supports: () => ({ supported: true, priority: 0 }),
+      runAttempt: vi.fn(),
+    };
+    builtInOpenClawHarnesses.add(harness);
+    return harness;
+  },
+  isBuiltInOpenClawAgentHarness: (harness: AgentHarness) => builtInOpenClawHarnesses.has(harness),
+}));
+
+vi.mock("./harness/host-capability.js", () => {
   return {
-    ...actual,
-    createAgentHarnessHostCapabilities: (
-      params: Parameters<typeof actual.createAgentHarnessHostCapabilities>[0],
-    ) => {
+    createAgentHarnessHostCapabilities: (params: unknown) => {
       createAgentHarnessHostCapabilitiesMock(params);
-      return actual.createAgentHarnessHostCapabilities(params);
+      return { capabilities: {}, close: vi.fn() };
     },
   };
 });
@@ -303,15 +314,9 @@ vi.mock("../logging/diagnostic.js", () => ({
   },
 }));
 
-vi.mock("../config/sessions/session-accessor.js", async () => {
-  const actual = await vi.importActual<typeof import("../config/sessions/session-accessor.js")>(
-    "../config/sessions/session-accessor.js",
-  );
-  return {
-    ...actual,
-    loadTranscriptEvents: (...args: unknown[]) => loadTranscriptEventsMock(...args),
-  };
-});
+vi.mock("../config/sessions/session-accessor.js", () => ({
+  loadTranscriptEvents: (...args: unknown[]) => loadTranscriptEventsMock(...args),
+}));
 
 const { runBtwSideQuestion } = await import("./btw.js");
 const { clearAgentHarnesses, registerAgentHarness } = await import("./harness/registry.js");
@@ -1407,34 +1412,6 @@ describe("runBtwSideQuestion", () => {
     expect(mockArg(codexSideQuestionMock, 0, 0)).toMatchObject({ toolsAllow: [] });
   });
 
-  it("prepares a narrow global policy before calling a plugin side-question hook", async () => {
-    const codexSideQuestionMock = registerCodexSideQuestionHarness();
-    mockOpenAIPlatformProfile();
-    resolveModelWithRegistryMock.mockReturnValue({
-      provider: "openai",
-      id: "gpt-5.5",
-      api: "openai-responses",
-    });
-    resolveModelAsyncMock.mockResolvedValue({
-      model: {
-        provider: "openai",
-        id: "gpt-5.5",
-        api: "openai-responses",
-        baseUrl: "https://api.openai.com/v1",
-      },
-    });
-
-    await runSideQuestion({
-      cfg: { tools: { allow: ["message"] } } as never,
-      provider: "openai",
-      model: "gpt-5.5",
-      sessionKey: DEFAULT_SESSION_KEY,
-    });
-
-    expect(codexSideQuestionMock).toHaveBeenCalledOnce();
-    expect(mockArg(codexSideQuestionMock, 0, 0)).toMatchObject({ toolsAllow: [] });
-  });
-
   it("does not fall back to the direct provider call when Codex lacks BTW support", async () => {
     registerAgentHarness({
       id: "codex",