fix(app-tauri,frontend): la fenêtre Tâches planifiées s'affiche en mode détaché — #359 (QA verte)

cause: le panneau Tâches planifiées n'avait aucune variante dans l'enum ViewPanel, open_view_window("scheduledTasks") rejetait INVALID et detachPanel ne touchait le placement qu'en cas de succès — même famille que #299, aucun effet visible ni message.
fix: variante ViewPanel::ScheduledTasks avec contrat stable label view-scheduledTasks / url index.html?panel=scheduledTasks / titre « Scheduled tasks », identité persistée des fenêtres view-scheduledTasks acceptée à la restauration #50; frontend ViewWindow rend le ScheduledTasksPanel du projet focalisé et ProjectsView expose le placement Fenêtre détachée via WindowGateway; retrait de la variante Projects devenue morte après #315 — le panneau Projects (coquille de la fenêtre principale) n'est plus détachable, refus INVALID gardé par tests.
QA verte: view_window_tests dont scheduled_tasks_view_window_contract_is_stable et projects_panel_is_not_detachable, persisted_identity_accepts_scheduled_tasks_view_labels, frontend ViewWindow/window gateway/ProjectsView.detach verts.

frontend/src/adapters/window.test.ts

@@ -41,6 +41,14 @@ describe("TauriWindowGateway (#23)", () => {
     });
   });
 
+  it("passes scheduledTasks unchanged to the detached-window command", async () => {
+    await new TauriWindowGateway().openViewWindow("scheduledTasks");
+
+    expect(invoke).toHaveBeenCalledWith("open_view_window", {
+      panel: "scheduledTasks",
+    });
+  });
+
   it("opens plugin layout windows through the backend command", async () => {
     invoke.mockResolvedValueOnce({
       label: "view-plugin-layout",

frontend/src/app/ViewWindow.test.tsx

@@ -10,6 +10,7 @@ import { render, screen, waitFor, act, fireEvent } from "@testing-library/react"
 
 import { DIProvider } from "@/app/di";
 import {
+  createMockGateways,
   MockAgentGateway,
   MockFocusedProjectGateway,
   MockProjectGateway,
@@ -66,6 +67,13 @@ describe("parseViewWindowParams (#47)", () => {
     });
   });
 
+  it("accepts the detachable scheduled tasks panel", () => {
+    expect(parseViewWindowParams("?panel=scheduledTasks")).toEqual({
+      kind: "panel",
+      panel: "scheduledTasks",
+    });
+  });
+
   it("parses a plugin layout window query from the backend base64url contract", () => {
     expect(
       parseViewWindowParams(
@@ -170,6 +178,29 @@ describe("PluginLayoutWindow (#143)", () => {
 });
 
 describe("ViewWindow (#47)", () => {
+  it("renders ScheduledTasksPanel for a focused project", async () => {
+    const gateways = createMockGateways();
+    const project = await gateways.project.createProject("alpha", "/p/a");
+    const focusedProject = new MockFocusedProjectGateway();
+    gateways.focusedProject = focusedProject;
+    await focusedProject.setFocusedProject({
+      id: project.id,
+      name: project.name,
+      root: project.root,
+    });
+
+    render(
+      <DIProvider gateways={gateways}>
+        <ViewWindow panel="scheduledTasks" />
+      </DIProvider>,
+    );
+
+    await waitFor(() => expect(screen.getByText("· alpha")).toBeTruthy());
+    expect(screen.getByRole("heading", { name: "Tâches planifiées", level: 1 })).toBeTruthy();
+    expect(await screen.findByRole("button", { name: "Nouvelle tâche planifiée" })).toBeTruthy();
+    expect(await screen.findByText("Aucune tâche planifiée pour ce projet")).toBeTruthy();
+  });
+
   it("keeps the latest focused project when the initial snapshot is delayed", async () => {
     const system = new MockSystemGateway();
     const project = new MockProjectGateway();

frontend/src/features/projects/ProjectsView.detach.test.tsx

@@ -92,6 +92,17 @@ describe("ProjectsView detach to OS window (#23)", () => {
     expect(screen.queryByRole("dialog", { name: "MCP" })).toBeNull();
   });
 
+  it("detaches scheduled tasks through WindowGateway", async () => {
+    const { windowGateway } = await renderWithProject();
+    const openViewWindow = vi.spyOn(windowGateway, "openViewWindow");
+
+    pickPlacement("Tâches planifiées", "Fenêtre détachée");
+
+    await waitFor(() => expect(openViewWindow).toHaveBeenCalledWith("scheduledTasks"));
+    expect(windowGateway.open.has("scheduledTasks")).toBe(true);
+    expect(screen.queryByRole("dialog", { name: "Tâches planifiées" })).toBeNull();
+  });
+
   it("detaches project settings through the same retry-safe window path", async () => {
     const { windowGateway } = await renderWithProject();