feat(tickets): attribution d'un sprint à la création via popup SprintPicker (#38)

Nouveau composant SprintPicker permettant de choisir un sprint lors de
la création d'un ticket depuis TicketsPanel ; export ajouté à l'index
des features tickets. Frontend-pur.

QA vert : tsc --noEmit exit 0, vitest 63 fichiers / 634 tests passés.

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

frontend/src/features/tickets/SprintPicker.test.tsx

@@ -0,0 +1,164 @@
+import { describe, it, expect, beforeEach, vi } from "vitest";
+import { fireEvent, render, screen } from "@testing-library/react";
+
+import { DIProvider } from "@/app/di";
+import { MockSystemGateway, MockTicketGateway } from "@/adapters/mock";
+import type { Gateways } from "@/ports";
+import { SprintPicker } from "./SprintPicker";
+
+const PROJECT_ID = "project-sprint-picker";
+
+function renderPicker(
+  ticket: MockTicketGateway,
+  props: Partial<React.ComponentProps<typeof SprintPicker>> = {},
+) {
+  const onSelect = vi.fn();
+  const onClose = vi.fn();
+  const gateways = { ticket } as unknown as Gateways;
+  const utils = render(
+    <DIProvider gateways={gateways}>
+      <SprintPicker
+        open
+        projectId={PROJECT_ID}
+        onSelect={onSelect}
+        onClose={onClose}
+        {...props}
+      />
+    </DIProvider>,
+  );
+  return { ...utils, onSelect, onClose };
+}
+
+/** Seeds two ordered sprints. */
+function seedSprints(ticket: MockTicketGateway) {
+  const beta = ticket._seedSprint(PROJECT_ID, {
+    id: "s2",
+    order: 2,
+    name: "Beta",
+    ticketCount: 3,
+  });
+  const alpha = ticket._seedSprint(PROJECT_ID, {
+    id: "s1",
+    order: 1,
+    name: "Alpha",
+  });
+  return { alpha, beta };
+}
+
+describe("SprintPicker (#38)", () => {
+  let system: MockSystemGateway;
+  let ticket: MockTicketGateway;
+
+  beforeEach(() => {
+    system = new MockSystemGateway();
+    ticket = new MockTicketGateway(system);
+  });
+
+  it("renders nothing when closed", () => {
+    const gateways = { ticket } as unknown as Gateways;
+    const { container } = render(
+      <DIProvider gateways={gateways}>
+        <SprintPicker
+          open={false}
+          projectId={PROJECT_ID}
+          onSelect={vi.fn()}
+          onClose={vi.fn()}
+        />
+      </DIProvider>,
+    );
+    expect(container.querySelector('[role="dialog"]')).toBeNull();
+  });
+
+  it("lists the project's sprints (ordered) plus a « Sans sprint » entry", async () => {
+    seedSprints(ticket);
+    renderPicker(ticket);
+
+    // "Sans sprint" is always present.
+    expect(screen.getByLabelText("select no sprint")).toBeTruthy();
+
+    // Both sprints appear once loaded, ordered by `order` (Alpha before Beta).
+    await screen.findByLabelText("select sprint Alpha");
+    const options = screen
+      .getAllByRole("option")
+      .map((n) => n.getAttribute("aria-label"));
+    expect(options).toEqual([
+      "select no sprint",
+      "select sprint Alpha",
+      "select sprint Beta",
+    ]);
+  });
+
+  it("selecting a sprint hands back the sprint and closes", async () => {
+    const { alpha } = seedSprints(ticket);
+    const { onSelect, onClose } = renderPicker(ticket);
+
+    fireEvent.click(await screen.findByLabelText("select sprint Alpha"));
+
+    expect(onSelect).toHaveBeenCalledTimes(1);
+    expect(onSelect.mock.calls[0][0]).toMatchObject({
+      id: alpha.id,
+      name: "Alpha",
+    });
+    expect(onClose).toHaveBeenCalledTimes(1);
+  });
+
+  it("selecting « Sans sprint » hands back null and closes", async () => {
+    seedSprints(ticket);
+    const { onSelect, onClose } = renderPicker(ticket, {
+      selectedSprintId: "s1",
+    });
+
+    await screen.findByLabelText("select sprint Alpha");
+    fireEvent.click(screen.getByLabelText("select no sprint"));
+
+    expect(onSelect).toHaveBeenCalledTimes(1);
+    expect(onSelect.mock.calls[0][0]).toBeNull();
+    expect(onClose).toHaveBeenCalledTimes(1);
+  });
+
+  it("marks the currently-selected sprint as aria-selected", async () => {
+    seedSprints(ticket);
+    renderPicker(ticket, { selectedSprintId: "s2" });
+
+    const beta = await screen.findByLabelText("select sprint Beta");
+    expect(beta.getAttribute("aria-selected")).toBe("true");
+    expect(
+      screen.getByLabelText("select sprint Alpha").getAttribute("aria-selected"),
+    ).toBe("false");
+    // "Sans sprint" is not selected when a sprint id is active.
+    expect(
+      screen.getByLabelText("select no sprint").getAttribute("aria-selected"),
+    ).toBe("false");
+  });
+
+  it("shows an empty state when the project has no sprints", async () => {
+    renderPicker(ticket);
+    expect(await screen.findByText("No sprints yet.")).toBeTruthy();
+    // "Sans sprint" is still offered so the user can clear an assignment.
+    expect(screen.getByLabelText("select no sprint")).toBeTruthy();
+  });
+
+  it("closes on Escape and on backdrop click", async () => {
+    seedSprints(ticket);
+    const { onClose } = renderPicker(ticket);
+    await screen.findByLabelText("select sprint Alpha");
+
+    fireEvent.keyDown(document, { key: "Escape" });
+    expect(onClose).toHaveBeenCalledTimes(1);
+
+    const dialog = screen.getByRole("dialog");
+    const backdrop = dialog.parentElement as HTMLElement;
+    fireEvent.mouseDown(backdrop);
+    expect(onClose).toHaveBeenCalledTimes(2);
+  });
+
+  it("surfaces a listSprints failure", async () => {
+    vi.spyOn(ticket, "listSprints").mockRejectedValueOnce({
+      code: "INTERNAL",
+      message: "boom",
+    });
+    renderPicker(ticket);
+    const alert = await screen.findByRole("alert");
+    expect(alert.textContent).toContain("boom");
+  });
+});