feat(FN-1081): add dashboard nodes management workflow

- Add node API typings and client methods plus a polling useNodes hook with visibility-triggered refresh
- Introduce NodesView with NodeCard, AddNodeModal, and NodeDetailModal to register, inspect, update, health-check, and remove nodes
- Wire the Nodes surface into the app shell/header and add project node assignment UI with project card node badges
- Add unit coverage for useNodes, NodesView, NodeCard, Header, and ProjectCard behavior, plus node-specific dashboard styling

packages/dashboard/app/components/__tests__/NodesView.test.tsx

@@ -0,0 +1,139 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { render, screen, fireEvent } from "@testing-library/react";
+import { NodesView } from "../NodesView";
+import type { NodeInfo, ProjectInfo } from "../../api";
+import { useNodes } from "../../hooks/useNodes";
+import { useProjects } from "../../hooks/useProjects";
+
+vi.mock("../../hooks/useNodes", () => ({
+  useNodes: vi.fn(),
+}));
+
+vi.mock("../../hooks/useProjects", () => ({
+  useProjects: vi.fn(),
+}));
+
+const mockUseNodes = vi.mocked(useNodes);
+const mockUseProjects = vi.mocked(useProjects);
+
+function makeNode(overrides: Partial<NodeInfo> = {}): NodeInfo {
+  return {
+    id: "node-1",
+    name: "Primary Node",
+    type: "local",
+    status: "online",
+    maxConcurrent: 2,
+    createdAt: "2026-01-01T00:00:00.000Z",
+    updatedAt: "2026-01-01T00:00:00.000Z",
+    ...overrides,
+  };
+}
+
+function makeProject(overrides: Partial<ProjectInfo> = {}): ProjectInfo {
+  return {
+    id: "proj-1",
+    name: "Project One",
+    path: "/workspace/project-one",
+    status: "active",
+    isolationMode: "in-process",
+    createdAt: "2026-01-01T00:00:00.000Z",
+    updatedAt: "2026-01-01T00:00:00.000Z",
+    ...overrides,
+  };
+}
+
+function makeUseNodesResult(overrides: Partial<ReturnType<typeof useNodes>> = {}): ReturnType<typeof useNodes> {
+  return {
+    nodes: [],
+    loading: false,
+    error: null,
+    refresh: vi.fn().mockResolvedValue(undefined),
+    register: vi.fn().mockResolvedValue(makeNode()),
+    update: vi.fn().mockResolvedValue(makeNode()),
+    unregister: vi.fn().mockResolvedValue(undefined),
+    healthCheck: vi.fn().mockResolvedValue(undefined),
+    ...overrides,
+  };
+}
+
+beforeEach(() => {
+  mockUseProjects.mockReturnValue({
+    projects: [],
+    loading: false,
+    error: null,
+    refresh: vi.fn().mockResolvedValue(undefined),
+    register: vi.fn(),
+    update: vi.fn(),
+    unregister: vi.fn(),
+  });
+});
+
+describe("NodesView", () => {
+  it("renders node cards and stats", () => {
+    mockUseProjects.mockReturnValue({
+      projects: [makeProject({ nodeId: "node-1" }), makeProject({ id: "proj-2", nodeId: "node-2" })],
+      loading: false,
+      error: null,
+      refresh: vi.fn().mockResolvedValue(undefined),
+      register: vi.fn(),
+      update: vi.fn(),
+      unregister: vi.fn(),
+    });
+
+    mockUseNodes.mockReturnValue(makeUseNodesResult({
+      nodes: [
+        makeNode({ id: "node-1", name: "Alpha", status: "online", type: "local" }),
+        makeNode({ id: "node-2", name: "Beta", status: "offline", type: "remote", url: "https://beta.node" }),
+      ],
+    }));
+
+    render(<NodesView addToast={vi.fn()} />);
+
+    expect(screen.getByText("Alpha")).toBeDefined();
+    expect(screen.getByText("Beta")).toBeDefined();
+    expect(screen.getByText("2 registered")).toBeDefined();
+    expect(screen.getByTestId("nodes-stat-total").textContent).toContain("2");
+    expect(screen.getByTestId("nodes-stat-online").textContent).toContain("1");
+    expect(screen.getByTestId("nodes-stat-offline").textContent).toContain("1");
+    expect(screen.getByTestId("nodes-stat-remote").textContent).toContain("1");
+  });
+
+  it("renders empty state when there are no nodes", () => {
+    mockUseNodes.mockReturnValue(makeUseNodesResult({ nodes: [] }));
+
+    render(<NodesView addToast={vi.fn()} />);
+
+    expect(screen.getByText("No nodes are registered yet.")).toBeDefined();
+    expect(screen.getByText("Add First Node")).toBeDefined();
+  });
+
+  it("opens Add Node modal when Add Node button is clicked", () => {
+    mockUseNodes.mockReturnValue(makeUseNodesResult({ nodes: [] }));
+
+    render(<NodesView addToast={vi.fn()} />);
+
+    fireEvent.click(screen.getByText("Add Node"));
+    expect(screen.getByRole("dialog", { name: "Add Node" })).toBeDefined();
+  });
+
+  it("opens Node Detail modal when a node card is clicked", () => {
+    mockUseProjects.mockReturnValue({
+      projects: [makeProject({ nodeId: "node-1" })],
+      loading: false,
+      error: null,
+      refresh: vi.fn().mockResolvedValue(undefined),
+      register: vi.fn(),
+      update: vi.fn(),
+      unregister: vi.fn(),
+    });
+
+    mockUseNodes.mockReturnValue(makeUseNodesResult({
+      nodes: [makeNode({ id: "node-1", name: "Alpha Node" })],
+    }));
+
+    render(<NodesView addToast={vi.fn()} />);
+
+    fireEvent.click(screen.getByText("Alpha Node"));
+    expect(screen.getByRole("dialog", { name: "Node details for Alpha Node" })).toBeDefined();
+  });
+});