refactor(webui): centralize native runtime access (#4769)

webui/src/tests/runtime.test.ts

@@ -0,0 +1,45 @@
+import { afterEach, describe, expect, it, vi } from "vitest";
+
+import { getRuntimeHost, isNativeRuntime } from "@/lib/runtime";
+
+afterEach(() => {
+  Reflect.deleteProperty(window, "nanobotHost");
+});
+
+describe("runtime host facade", () => {
+  it("defaults to browser runtime without host actions", () => {
+    const host = getRuntimeHost();
+
+    expect(host.surface).toBe("browser");
+    expect(host.pickFolder).toBeUndefined();
+    expect(isNativeRuntime()).toBe(false);
+  });
+
+  it("wraps native host actions behind the runtime facade", async () => {
+    const pickFolder = vi.fn(async () => "/tmp/project");
+    const restartEngine = vi.fn(async () => undefined);
+    Object.defineProperty(window, "nanobotHost", {
+      configurable: true,
+      value: {
+        getRuntimeInfo: vi.fn(),
+        restartEngine,
+        pickFolder,
+        openLogs: vi.fn(async () => undefined),
+        exportDiagnostics: vi.fn(async () => "/tmp/diagnostics.txt"),
+      },
+    });
+
+    const host = getRuntimeHost();
+
+    expect(host.surface).toBe("native");
+    expect(isNativeRuntime()).toBe(true);
+    await expect(host.pickFolder?.()).resolves.toBe("/tmp/project");
+    await host.restartEngine?.();
+    expect(pickFolder).toHaveBeenCalledTimes(1);
+    expect(restartEngine).toHaveBeenCalledTimes(1);
+  });
+
+  it("treats server-reported native surface as native for UI labels", () => {
+    expect(isNativeRuntime("native")).toBe(true);
+  });
+});