feat(FN-1073): add desktop CLI workflow and packaging support

- Add new `fn desktop` CLI command with argument handling and comprehensive command/bin tests
- Implement desktop build and hot-reload dev scripts and wire package scripts/dependencies for Electron workflows
- Add electron-builder configuration and desktop main-process/integration test coverage to stabilize packaging behavior
- Document desktop development and usage in README files and include a changeset for the published CLI package

packages/cli/src/__tests__/bin.test.ts

@@ -2,6 +2,7 @@ import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
 
 const runTaskCreate = vi.fn();
 const runTaskList = vi.fn();
+const runDesktop = vi.fn();
 const runTaskPlan = vi.fn();
 const runTaskImportFromGitHub = vi.fn();
 const runSettingsShow = vi.fn();
@@ -36,6 +37,10 @@ vi.mock("../commands/dashboard.js", () => ({
   runDashboard: vi.fn(),
 }));
 
+vi.mock("../commands/desktop.js", () => ({
+  runDesktop,
+}));
+
 vi.mock("../commands/task.js", () => ({
   runTaskCreate,
   runTaskList,
@@ -272,6 +277,16 @@ describe("bin", () => {
     expect(errorSpy).toHaveBeenCalledWith("Unknown subcommand: node wat");
   });
 
+  it("routes desktop command flags", async () => {
+    await runBin(["desktop", "--dev", "--paused", "--interactive"]);
+
+    expect(runDesktop).toHaveBeenCalledWith({
+      paused: true,
+      dev: true,
+      interactive: true,
+    });
+  });
+
   it("rejects duplicate --project flags", async () => {
     await expect(runBin(["task", "list", "--project", "one", "-P", "two"]))
       .rejects.toThrow("Duplicate --project flag. Specify a project only once.");