feat(ui): add maintainer activation preview card

apps/gittensory-ui/src/components/site/app-panels/activation-preview.test.tsx

@@ -0,0 +1,159 @@
+import { render, screen, fireEvent, waitFor } from "@testing-library/react";
+import { beforeEach, describe, expect, it, vi } from "vitest";
+
+// Mock the API layer so the component never touches the network.
+const { apiFetch } = vi.hoisted(() => ({ apiFetch: vi.fn() }));
+vi.mock("@/lib/api/request", () => ({ apiFetch: (...args: unknown[]) => apiFetch(...args) }));
+vi.mock("@/lib/api/origin", () => ({ getApiOrigin: () => "https://api.test" }));
+
+import { ActivationPreview } from "@/components/site/app-panels/activation-preview";
+
+const REVIEWABILITY = [{ pr: "acme/widgets#1" }];
+
+const BASE_PREVIEW = {
+  repoFullName: "acme/widgets",
+  generatedAt: "2026-07-05T00:00:00.000Z",
+  currentGateMode: "off" as const,
+  aiReviewConfigured: false,
+  evaluatedCount: 3,
+  withFindingsCount: 2,
+  findingCodeCounts: [{ code: "missing_tests", count: 2 }],
+  samples: [
+    {
+      number: 12,
+      title: "Add cursor pagination",
+      severity: "warning" as const,
+      findingCount: 1,
+      findings: [],
+    },
+    {
+      number: 11,
+      title: "Fix flaky test",
+      severity: "info" as const,
+      findingCount: 0,
+      findings: [],
+    },
+  ],
+  recommendedAction: "enable_advisory" as const,
+  summary:
+    "Gittensory reviewed your 3 most recent pull request(s) and would have surfaced guidance on 2 of them.",
+};
+
+describe("ActivationPreview", () => {
+  beforeEach(() => {
+    apiFetch.mockReset();
+  });
+
+  it("shows a loading state, then renders the real preview data on load", async () => {
+    apiFetch.mockResolvedValue({ ok: true, data: BASE_PREVIEW });
+    render(<ActivationPreview reviewability={REVIEWABILITY} />);
+
+    expect(screen.getByText(/Building activation preview/i)).toBeTruthy();
+    await waitFor(() => expect(screen.getByText(BASE_PREVIEW.summary)).toBeTruthy());
+    expect(screen.getByText("Add cursor pagination")).toBeTruthy();
+    expect(screen.getByText("missing_tests × 2")).toBeTruthy();
+    expect(apiFetch).toHaveBeenCalledWith(
+      expect.stringContaining("/v1/repos/acme/widgets/activation-preview"),
+      expect.objectContaining({ label: "Activation preview" }),
+    );
+  });
+
+  it("renders an error state with the failure message when the preview fails to load", async () => {
+    apiFetch.mockResolvedValue({ ok: false, message: "503 Service Unavailable" });
+    render(<ActivationPreview reviewability={REVIEWABILITY} />);
+
+    await waitFor(() =>
+      expect(screen.getByText(/Couldn't load the activation preview/i)).toBeTruthy(),
+    );
+    expect(screen.getByText("503 Service Unavailable")).toBeTruthy();
+  });
+
+  it("renders an empty state when zero pull requests have been evaluated", async () => {
+    apiFetch.mockResolvedValue({
+      ok: true,
+      data: {
+        ...BASE_PREVIEW,
+        evaluatedCount: 0,
+        withFindingsCount: 0,
+        samples: [],
+        findingCodeCounts: [],
+        recommendedAction: null,
+      },
+    });
+    render(<ActivationPreview reviewability={REVIEWABILITY} />);
+
+    await waitFor(() => expect(screen.getByText(/No recent pull requests yet/i)).toBeTruthy());
+  });
+
+  it("shows the enable-advisory action, posts activation, and reflects the enabled state after the round-trip", async () => {
+    apiFetch.mockResolvedValueOnce({ ok: true, data: BASE_PREVIEW });
+    render(<ActivationPreview reviewability={REVIEWABILITY} />);
+    await waitFor(() => expect(screen.getByText(BASE_PREVIEW.summary)).toBeTruthy());
+
+    const activateButton = screen.getByRole("button", { name: /enable advisory mode/i });
+
+    apiFetch.mockResolvedValueOnce({
+      ok: true,
+      data: {
+        repoFullName: "acme/widgets",
+        gateCheckMode: "enabled",
+        reviewCheckMode: "required",
+        checkRunMode: "enabled",
+        linkedIssueGateMode: "advisory",
+        duplicatePrGateMode: "advisory",
+        qualityGateMode: "advisory",
+      },
+    });
+    // Reload after activation reports the gate is now on — the button should disappear.
+    apiFetch.mockResolvedValueOnce({
+      ok: true,
+      data: { ...BASE_PREVIEW, currentGateMode: "enabled", recommendedAction: null },
+    });
+
+    fireEvent.click(activateButton);
+
+    await waitFor(() =>
+      expect(
+        screen.getByText(/Advisory mode enabled\. Gittensory will now surface guidance/i),
+      ).toBeTruthy(),
+    );
+    await waitFor(() => expect(screen.getByText(/Advisory mode is already enabled/i)).toBeTruthy());
+    expect(screen.queryByRole("button", { name: /enable advisory mode/i })).toBeNull();
+
+    const postCall = apiFetch.mock.calls.find(
+      ([, opts]) => (opts as { method?: string })?.method === "POST",
+    );
+    expect(postCall?.[0]).toContain("/v1/repos/acme/widgets/activation");
+  });
+
+  it("surfaces the error message inline when activation fails, without touching the preview data", async () => {
+    apiFetch.mockResolvedValueOnce({ ok: true, data: BASE_PREVIEW });
+    render(<ActivationPreview reviewability={REVIEWABILITY} />);
+    await waitFor(() => expect(screen.getByText(BASE_PREVIEW.summary)).toBeTruthy());
+
+    apiFetch.mockResolvedValueOnce({ ok: false, message: "403 Forbidden" });
+
+    fireEvent.click(screen.getByRole("button", { name: /enable advisory mode/i }));
+
+    await waitFor(() => expect(screen.getByText("403 Forbidden")).toBeTruthy());
+    // Still showing the previously-loaded preview, unchanged.
+    expect(screen.getByText(BASE_PREVIEW.summary)).toBeTruthy();
+  });
+
+  it("falls back to a manual owner/repo entry when no repos are registered yet", () => {
+    render(<ActivationPreview reviewability={[]} />);
+    expect(screen.getByText(/No registered repositories detected yet/i)).toBeTruthy();
+    expect(screen.getByText(/Enter an installed repository to preview activation\./i)).toBeTruthy();
+  });
+
+  it("shows the 'settings unavailable' copy for a typed repo string that doesn't parse as owner\\/repo", async () => {
+    apiFetch.mockResolvedValue({ ok: true, data: BASE_PREVIEW });
+    render(<ActivationPreview reviewability={REVIEWABILITY} />);
+    await waitFor(() => expect(screen.getByText(BASE_PREVIEW.summary)).toBeTruthy());
+
+    fireEvent.change(screen.getByPlaceholderText("owner/repo"), {
+      target: { value: "not-a-valid-slug" },
+    });
+    expect(screen.getByText(/Settings are unavailable for this repository\./i)).toBeTruthy();
+  });
+});