feat(ui): refonte menus & fenêtres — menu unique Panneaux et onglets projet (#26)

Sous-menus flyout dans MenuBar ; ProjectsView expose un menu unique
Panneaux et supprime les menus View/Window/File ainsi que le sélecteur
de projet ; ProjectTabs gère les onglets et le bouton +. Tests migrés
en conséquence.

QA vert : tsc --noEmit exit 0, vitest 62 fichiers / 616 tests passés,
invariants préservés.

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

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

@@ -75,11 +75,19 @@ function tablist() {
 }
 
 /**
- * Opens a menu-bar dropdown item (#16 chrome). `menu` is a top-level menu
- * ("File"/"View"), `item` a panel entry ("Work", "Agents", "Projects…", …).
- * The panel then shows in its floating window.
+ * Opens a panel floating via the single « Panneaux » menu (#26): click the menu,
+ * click the panel entry (opens its placement submenu), then pick « Flottant ».
+ * `panelTitle` is the panel's human title ("Work state", "Project context",
+ * "Agents", "Git", "Projects", …).
  */
-function openPanel(menu: string, item: string) {
+function openPanel(panelTitle: string) {
+  fireEvent.click(screen.getByRole("button", { name: "Panneaux" }));
+  fireEvent.click(screen.getByRole("button", { name: panelTitle }));
+  fireEvent.click(screen.getByRole("button", { name: "Flottant" }));
+}
+
+/** Clicks an item in a flat top-level menu (e.g. Settings). */
+function openMenuItem(menu: string, item: string) {
   fireEvent.click(screen.getByRole("button", { name: menu }));
   fireEvent.click(screen.getByRole("button", { name: item }));
 }
@@ -97,7 +105,7 @@ describe("ProjectsView (with MockProjectGateway)", () => {
     expect(tab.getAttribute("aria-selected")).toBe("true");
     expect(within(tab).getByText("alpha")).toBeTruthy();
     // And it is listed in the projects manager (File → Projects…) with its root.
-    openPanel("File", "Projects…");
+    openPanel("Projects");
     expect(
       (await screen.findAllByText("/home/me/alpha")).length,
     ).toBeGreaterThan(0);
@@ -116,7 +124,7 @@ describe("ProjectsView (with MockProjectGateway)", () => {
 
     // Open the projects manager window so the list persists across activation
     // (the inline welcome list is replaced by the terminal grid once active).
-    openPanel("File", "Projects…");
+    openPanel("Projects");
 
     // Open alpha, then beta — re-querying the list after each activation.
     const openInList = (name: string) =>
@@ -155,12 +163,12 @@ describe("ProjectsView (with MockProjectGateway)", () => {
     fireEvent.click(screen.getByRole("button", { name: "Open" }));
     await screen.findByRole("tab", { name: "alpha" });
 
-    openPanel("View", "Work");
+    openPanel("Work state");
 
     expect(await screen.findByText("No agent work state.")).toBeTruthy();
   });
 
-  it("switches the active project from the always-visible project selector (#16)", async () => {
+  it("switches the active project via the tab-bar + button → Projects panel (#26)", async () => {
     const project = new MockProjectGateway();
     await project.createProject("alpha", "/p/a");
     await project.createProject("beta", "/p/b");
@@ -174,17 +182,15 @@ describe("ProjectsView (with MockProjectGateway)", () => {
     fireEvent.click(within(alphaLi).getByRole("button", { name: "Open" }));
     await screen.findByRole("tab", { name: "alpha" });
 
-    // The selector reflects the active project and lists all known projects.
-    fireEvent.click(screen.getByRole("button", { name: "Projet : alpha" }));
-    // Pick beta from the selector — it opens/activates without the Projects window.
-    fireEvent.click(screen.getByRole("button", { name: "beta" }));
+    // The "+" button opens the Projects panel (floating); pick beta from its
+    // known-projects list — no verbose "Projet : …" selector anymore.
+    fireEvent.click(screen.getByRole("button", { name: "open projects panel" }));
+    const betaLi = await waitFor(() =>
+      screen.getAllByRole("listitem").find((n) => within(n).queryByText("beta"))!,
+    );
+    fireEvent.click(within(betaLi).getByRole("button", { name: "Open" }));
 
-    await waitFor(() =>
-      expect(screen.getByRole("button", { name: "Projet : beta" })).toBeTruthy(),
-    );
-    await waitFor(() =>
-      expect(screen.getAllByRole("tab")).toHaveLength(2),
-    );
+    await waitFor(() => expect(screen.getAllByRole("tab")).toHaveLength(2));
     const betaTab = screen
       .getAllByRole("tab")
       .find((t) => within(t).queryByText("beta"))!;
@@ -200,12 +206,12 @@ describe("ProjectsView (with MockProjectGateway)", () => {
     expect(screen.queryByLabelText("ai profiles settings")).toBeNull();
 
     // Settings → AI Profiles swaps the main area to the profiles settings.
-    openPanel("Settings", "AI Profiles");
+    openMenuItem("Settings", "AI Profiles");
     expect(await screen.findByLabelText("ai profiles settings")).toBeTruthy();
     expect(screen.queryByLabelText("project name")).toBeNull();
 
     // Settings → Close AI Profiles returns to the project surface.
-    openPanel("Settings", "Close AI Profiles");
+    openMenuItem("Settings", "Close AI Profiles");
     await waitFor(() =>
       expect(screen.getByLabelText("project name")).toBeTruthy(),
     );
@@ -233,7 +239,7 @@ describe("ProjectsView (with MockProjectGateway)", () => {
 
     // Reopen the projects manager (the inline form is replaced by the grid once
     // a project is active), then create a second project at the same root.
-    openPanel("File", "Projects…");
+    openPanel("Projects");
     await createProject("beta", "/dup/root");
 
     const alert = await screen.findByRole("alert");
@@ -255,40 +261,40 @@ describe("ProjectsView (with MockProjectGateway)", () => {
     );
 
     // File → Projects… opens the projects manager window — form inputs visible.
-    openPanel("File", "Projects…");
+    openPanel("Projects");
     await waitFor(() =>
       expect(screen.getByLabelText("project name")).toBeTruthy(),
     );
 
     // View → Agents — agent form visible; project form window is replaced.
-    openPanel("View", "Agents");
+    openPanel("Agents");
     await waitFor(() =>
       expect(screen.getByLabelText("agent name")).toBeTruthy(),
     );
     expect(screen.queryByLabelText("project name")).toBeNull();
 
     // View → Context — shared project context editor visible.
-    openPanel("View", "Context");
+    openPanel("Project context");
     await waitFor(() =>
       expect(screen.getByLabelText("project context")).toBeTruthy(),
     );
     expect(screen.queryByLabelText("agent name")).toBeNull();
 
     // View → Templates — the "New template" button visible.
-    openPanel("View", "Templates");
+    openPanel("Templates");
     await waitFor(() =>
       expect(screen.getByRole("button", { name: "create template" })).toBeTruthy(),
     );
     expect(screen.queryByLabelText("agent name")).toBeNull();
 
     // View → Git — commit message input visible.
-    openPanel("View", "Git");
+    openPanel("Git");
     await waitFor(() =>
       expect(screen.getByLabelText("commit message")).toBeTruthy(),
     );
 
     // File → Projects… again — form accessible once more.
-    openPanel("File", "Projects…");
+    openPanel("Projects");
     await waitFor(() =>
       expect(screen.getByLabelText("project name")).toBeTruthy(),
     );
@@ -302,7 +308,7 @@ describe("ProjectsView (with MockProjectGateway)", () => {
 
     await screen.findByText("/p/a");
     fireEvent.click(screen.getByRole("button", { name: "Open" }));
-    openPanel("View", "Context");
+    openPanel("Project context");
 
     const editor = (await screen.findByLabelText(
       "project context",