test(frontend): verify PR hydration end-to-end for a normal project (#251)

Drives the real useWorkspaceQuery + real SessionsBoard / PullRequestsPage
for an ordinary project (from /api/v1/projects) whose session has an open PR,
mocking only the HTTP client and router. Confirms PR facts fetched from
/sessions/{id}/pr flow through the shared workspace cache into both the Board
card ("PR #278 · open") and the PR page row.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: neversettle17-101

frontend/src/renderer/components/PrHydration.integration.test.tsx

@@ -0,0 +1,100 @@
+import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
+import { render, screen } from "@testing-library/react";
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import type { ReactNode } from "react";
+
+// Drives the real useWorkspaceQuery + real Board / PR-page consumers end to end
+// for a normal project, mocking only the HTTP client and the router. Proves the
+// #251 fix: PR facts fetched from /pr flow through the shared workspace cache
+// into every consumer.
+const { getMock, navigateMock } = vi.hoisted(() => ({ getMock: vi.fn(), navigateMock: vi.fn() }));
+
+vi.mock("../lib/api-client", () => ({
+	apiClient: { GET: getMock, POST: vi.fn() },
+	apiErrorMessage: (e: unknown) => (e instanceof Error ? e.message : "error"),
+}));
+
+vi.mock("@tanstack/react-router", async (importOriginal) => {
+	const actual = await importOriginal<typeof import("@tanstack/react-router")>();
+	return { ...actual, useNavigate: () => navigateMock };
+});
+
+import { SessionsBoard } from "./SessionsBoard";
+import { PullRequestsPage } from "./PullRequestsPage";
+
+// One ordinary project with one worker session that has an open PR (#278).
+function respondWithProjectAndPR() {
+	getMock.mockImplementation(async (url: string, options?: { params?: { path?: { sessionId?: string } } }) => {
+		if (url === "/api/v1/projects") {
+			return { data: { projects: [{ id: "proj-1", name: "my-app", path: "/repo/my-app" }] }, error: undefined };
+		}
+		if (url === "/api/v1/sessions") {
+			return {
+				data: {
+					sessions: [
+						{
+							id: "sess-1",
+							projectId: "proj-1",
+							displayName: "fix the bug",
+							harness: "claude-code",
+							status: "pr_open",
+							isTerminated: false,
+							updatedAt: "2026-06-10T16:15:04Z",
+						},
+					],
+				},
+				error: undefined,
+			};
+		}
+		if (url === "/api/v1/sessions/{sessionId}/pr") {
+			expect(options?.params?.path?.sessionId).toBe("sess-1");
+			return {
+				data: {
+					sessionId: "sess-1",
+					prs: [
+						{
+							number: 278,
+							state: "open",
+							url: "https://github.com/aoagents/ReverbCode/pull/278",
+							ci: "passing",
+							review: "approved",
+							mergeability: "clean",
+							reviewComments: false,
+							updatedAt: "2026-06-10T16:15:04Z",
+						},
+					],
+				},
+				error: undefined,
+			};
+		}
+		throw new Error(`unexpected GET ${url}`);
+	});
+}
+
+function renderWithProviders(node: ReactNode) {
+	const queryClient = new QueryClient({ defaultOptions: { queries: { retry: false } } });
+	render(<QueryClientProvider client={queryClient}>{node}</QueryClientProvider>);
+}
+
+beforeEach(() => {
+	getMock.mockReset();
+	navigateMock.mockReset();
+	respondWithProjectAndPR();
+});
+
+describe("PR hydration for a normal project (#251)", () => {
+	it("renders the PR on the Board card instead of 'no PR yet'", async () => {
+		renderWithProviders(<SessionsBoard />);
+
+		expect(await screen.findByText("PR #278 · open")).toBeInTheDocument();
+		expect(screen.queryByText("no PR yet")).not.toBeInTheDocument();
+	});
+
+	it("lists the session on the PR page instead of being empty", async () => {
+		renderWithProviders(<PullRequestsPage />);
+
+		expect(await screen.findByText("#278")).toBeInTheDocument();
+		expect(screen.queryByText("No open pull requests.")).not.toBeInTheDocument();
+		expect(screen.getByText("fix the bug")).toBeInTheDocument();
+	});
+});