feat(workstate): UI live-state des conversations/délégations (Lot A frontend)

Ajoute le port et l'adaptateur workState (+ mock) côté frontend, le type domaine
associé, et la feature `workstate` (panneau ProjectWorkStatePanel + hook
useProjectWorkState) consommant le read-model live exposé par le backend.
Intègre le panneau dans ProjectsView. Tests verts (workstate + projects).

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

frontend/src/features/workstate/workstate.test.tsx

@@ -0,0 +1,111 @@
+import { describe, it, expect, vi } from "vitest";
+import { render, screen, waitFor } from "@testing-library/react";
+
+import { DIProvider } from "@/app/di";
+import { MockSystemGateway, MockWorkStateGateway } from "@/adapters/mock";
+import type { Gateways } from "@/ports";
+import { ProjectWorkStatePanel } from "./ProjectWorkStatePanel";
+
+const PROJECT_ID = "project-work-state-test";
+
+function renderPanel(
+  workState: MockWorkStateGateway = new MockWorkStateGateway(),
+  system: MockSystemGateway = new MockSystemGateway(),
+) {
+  const gateways = { workState, system } as unknown as Gateways;
+  return {
+    workState,
+    system,
+    ...render(
+      <DIProvider gateways={gateways}>
+        <ProjectWorkStatePanel projectId={PROJECT_ID} />
+      </DIProvider>,
+    ),
+  };
+}
+
+describe("ProjectWorkStatePanel", () => {
+  it("renders the empty state", async () => {
+    renderPanel();
+
+    expect(await screen.findByText("No agent work state.")).toBeTruthy();
+  });
+
+  it("renders an idle offline agent", async () => {
+    const workState = new MockWorkStateGateway();
+    workState._setProjectWorkState(PROJECT_ID, {
+      agents: [
+        {
+          agentId: "agent-1",
+          name: "Planner",
+          profileId: "codex",
+          busy: { state: "idle" },
+        },
+      ],
+    });
+
+    renderPanel(workState);
+
+    expect(await screen.findByText("Planner")).toBeTruthy();
+    expect(screen.getByText("Offline")).toBeTruthy();
+    expect(screen.getByText("Idle")).toBeTruthy();
+  });
+
+  it("renders a live busy agent with a short ticket", async () => {
+    const workState = new MockWorkStateGateway();
+    workState._setProjectWorkState(PROJECT_ID, {
+      agents: [
+        {
+          agentId: "agent-2",
+          name: "Builder",
+          profileId: "claude",
+          live: {
+            nodeId: "node-a",
+            sessionId: "session-a",
+            kind: "pty",
+          },
+          busy: {
+            state: "busy",
+            ticket: "4c65d981-da5e-412d-85ed-3b9779b670fa",
+            sinceMs: 123,
+          },
+        },
+      ],
+    });
+
+    renderPanel(workState);
+
+    expect(await screen.findByText("Builder")).toBeTruthy();
+    expect(screen.getByText("Live")).toBeTruthy();
+    expect(screen.getByText("Busy")).toBeTruthy();
+    expect(screen.getByLabelText("busy ticket 4c65d981")).toBeTruthy();
+  });
+
+  it("refreshes when a relevant domain event fires", async () => {
+    const workState = new MockWorkStateGateway();
+    const system = new MockSystemGateway();
+    renderPanel(workState, system);
+
+    await screen.findByText("No agent work state.");
+    const spy = vi.spyOn(workState, "getProjectWorkState");
+    workState._setProjectWorkState(PROJECT_ID, {
+      agents: [
+        {
+          agentId: "agent-3",
+          name: "Responder",
+          profileId: "gemini",
+          busy: { state: "busy", ticket: "ticket-123456789", sinceMs: 456 },
+        },
+      ],
+    });
+
+    system.emit({
+      type: "agentBusyChanged",
+      agentId: "agent-3",
+      busy: true,
+    });
+
+    expect(await screen.findByText("Responder")).toBeTruthy();
+    await waitFor(() => expect(spy).toHaveBeenCalled());
+  });
+});