test(web): scaffold vitest + RTL with Orchestrator seed suite (DEBT-043)

Wire vitest 4 + jsdom + @testing-library/{react,jest-dom,user-event}
+ @vitest/coverage-v8 through vite.config.ts (defineConfig from
vitest/config). src/test/setup.ts registers jest-dom matchers and
RTL cleanup. tsconfig.app.json picks up vitest/globals types.

Seed suite Orchestrator.test.tsx covers the three regressions
called out in DEBT-043: empty-state render, kind-filter toggling
triggers a scoped refetch, mocked stream callback prepends a row.

decnet_web/src/components/Orchestrator.test.tsx

@@ -0,0 +1,93 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { render, screen, waitFor, act } from '@testing-library/react';
+import userEvent from '@testing-library/user-event';
+import { MemoryRouter } from 'react-router-dom';
+
+import Orchestrator from './Orchestrator';
+import type {
+  OrchestratorStreamEvent,
+  UseOrchestratorStreamOptions,
+} from './useOrchestratorStream';
+
+vi.mock('../utils/api', () => ({
+  default: { get: vi.fn() },
+}));
+
+// Capture the live stream callback so tests can drive it manually.
+let capturedOnEvent:
+  | ((event: OrchestratorStreamEvent) => void)
+  | null = null;
+vi.mock('./useOrchestratorStream', () => ({
+  useOrchestratorStream: (opts: UseOrchestratorStreamOptions) => {
+    capturedOnEvent = opts.onEvent;
+  },
+}));
+
+import api from '../utils/api';
+const apiGet = api.get as ReturnType<typeof vi.fn>;
+
+const renderPage = () =>
+  render(
+    <MemoryRouter initialEntries={['/orchestrator']}>
+      <Orchestrator />
+    </MemoryRouter>,
+  );
+
+describe('Orchestrator', () => {
+  beforeEach(() => {
+    capturedOnEvent = null;
+    apiGet.mockReset();
+  });
+
+  it('renders the empty state when the API returns no events', async () => {
+    apiGet.mockResolvedValueOnce({ data: { data: [], total: 0 } });
+
+    renderPage();
+
+    expect(await screen.findByText(/NO ORCHESTRATOR ACTIVITY YET/i)).toBeInTheDocument();
+    // The kind=all path advertises the orchestrator command, not the emailgen one.
+    expect(screen.getByText(/decnet orchestrate/i)).toBeInTheDocument();
+  });
+
+  it('switches the kind filter and refetches scoped to that kind', async () => {
+    apiGet.mockResolvedValue({ data: { data: [], total: 0 } });
+
+    renderPage();
+    await waitFor(() => expect(apiGet).toHaveBeenCalledTimes(1));
+    expect(apiGet.mock.calls[0][0]).toMatch(/^\/orchestrator\/events\?limit=50&offset=0$/);
+
+    await userEvent.click(screen.getByRole('tab', { name: /^email$/ }));
+
+    await waitFor(() =>
+      expect(apiGet.mock.calls.some((c) => /kind=email/.test(c[0]))).toBe(true),
+    );
+    expect(screen.getByRole('tab', { name: /^email$/ })).toHaveAttribute('aria-selected', 'true');
+  });
+
+  it('prepends a row when the live stream pushes a traffic event', async () => {
+    apiGet.mockResolvedValueOnce({ data: { data: [], total: 0 } });
+
+    renderPage();
+    await waitFor(() => expect(capturedOnEvent).not.toBeNull());
+
+    act(() => {
+      capturedOnEvent!({
+        name: 'traffic',
+        ts: new Date().toISOString(),
+        payload: {
+          kind: 'traffic',
+          protocol: 'http',
+          action: 'GET /admin',
+          src_decky_uuid: 'aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee',
+          dst_decky_uuid: 'ffffffff-1111-2222-3333-444444444444',
+          success: true,
+          payload: '{}',
+        },
+      });
+    });
+
+    expect(await screen.findByText('GET /admin')).toBeInTheDocument();
+    // 1 event shown after a single push.
+    expect(screen.getByText(/1 EVENTS SHOWN/i)).toBeInTheDocument();
+  });
+});