fix(ticket #7): ajoute le bouton Annuler aux notifications de fin de background task

frontend/src/features/projects/ProjectsView.ls7.test.tsx

@@ -268,7 +268,7 @@ describe("ProjectsView — LS7 conversation viewer integration", () => {
     const toast = await screen.findByRole("button", {
       name: /Appel Main -> DevBackend terminé/i,
     });
-    expect(within(toast).getByText("Task task-ren")).toBeTruthy();
+    expect(within(toast).getByText("alpha · Task task-ren")).toBeTruthy();
 
     fireEvent.click(toast);
 
@@ -346,7 +346,7 @@ describe("ProjectsView — LS7 conversation viewer integration", () => {
     const toast = await screen.findByRole("button", {
       name: /Background task failed/i,
     });
-    expect(within(toast).getByText("agent-ge · task-gen")).toBeTruthy();
+    expect(within(toast).getByText("alpha · agent-ge · task-gen")).toBeTruthy();
 
     fireEvent.click(toast);
 
@@ -355,4 +355,38 @@ describe("ProjectsView — LS7 conversation viewer integration", () => {
     ).toBeNull();
     expect(await screen.findByText("Work")).toBeTruthy();
   });
+
+  it("prefixes task toast context with a truncatable project-name line and falls back when unresolved", async () => {
+    const project = new MockProjectGateway();
+    const created = await project.createProject(
+      "alpha with a very long project name that must stay on one line",
+      "/p/a",
+    );
+    const system = new MockSystemGateway();
+    renderView(project, { system });
+
+    await openProjectAndWorkTab("/p/a");
+    system.emit({
+      type: "backgroundTaskChanged",
+      projectId: created.id,
+      agentId: "agent-long-name-context",
+      taskId: "task-long-name-context",
+      state: "completed",
+    });
+    system.emit({
+      type: "backgroundTaskChanged",
+      projectId: "project-not-in-view",
+      agentId: "agent-fallback-context",
+      taskId: "task-fallback-context",
+      state: "failed",
+    });
+
+    const longNameLine = await screen.findByText(
+      "alpha with a very long project name that must stay on one line · agent-lo · task-lon",
+    );
+    expect(longNameLine.className).toContain("truncate");
+    expect(
+      await screen.findByText("Projet inconnu · agent-fa · task-fal"),
+    ).toBeTruthy();
+  });
 });

frontend/src/features/projects/ProjectsView.tsx

@@ -33,7 +33,7 @@
  * open; the project tab bar (`role="tablist"`) is always present.
  */
 
-import { useEffect, useState, type ReactNode } from "react";
+import { useEffect, useMemo, useState, type ReactNode } from "react";
 
 import type { Agent, DomainEvent, LayoutInfo } from "@/domain";
 import { LayoutGrid, LayoutTabs } from "@/features/layout";
@@ -99,6 +99,7 @@ interface BackgroundTaskToast {
   taskId: string;
   state: string;
   title: string;
+  projectName: string;
   subtitle: string;
   conversationId?: string;
 }
@@ -135,6 +136,13 @@ function agentLabel(agents: Agent[], agentId: string): string {
   );
 }
 
+function projectToastName(
+  projectNameById: ReadonlyMap<string, string>,
+  projectId: string,
+): string {
+  return projectNameById.get(projectId) ?? "Projet inconnu";
+}
+
 function rendezvousToastStateLabel(state: string): string {
   switch (state) {
     case "completed":
@@ -190,6 +198,12 @@ export function ProjectsView() {
   const [taskToasts, setTaskToasts] = useState<BackgroundTaskToast[]>([]);
 
   const active = vm.openTabs.find((t) => t.id === vm.activeTabId) ?? null;
+  const projectNameById = useMemo(() => {
+    const names = new Map<string, string>();
+    for (const project of vm.projects) names.set(project.id, project.name);
+    for (const tab of vm.openTabs) names.set(tab.id, tab.name);
+    return names;
+  }, [vm.projects, vm.openTabs]);
 
   // `gitRepository` signal for the plugin `when` mini-language (#43, F3 —
   // Architect-mandated, blocking for #43 closure): whether the *current*
@@ -290,6 +304,7 @@ export function ProjectsView() {
           title: labels
             ? `Appel ${labels.requester} -> ${labels.target} ${rendezvousToastStateLabel(event.state)}`
             : `Background task ${event.state}`,
+          projectName: projectToastName(projectNameById, event.projectId),
           subtitle: labels
             ? `Task ${shortTaskId(event.taskId)}`
             : `${shortTaskId(event.agentId)} · ${shortTaskId(event.taskId)}`,
@@ -310,7 +325,7 @@ export function ProjectsView() {
       cancelled = true;
       unsubscribe?.();
     };
-  }, [agent, system]);
+  }, [agent, projectNameById, system]);
 
   const activeLayoutKind = activeLayout?.kind ?? "terminal";
 
@@ -913,7 +928,7 @@ export function ProjectsView() {
                 {toast.title}
               </span>
               <span className="mt-0.5 block truncate text-xs text-muted">
-                {toast.subtitle}
+                {toast.projectName} · {toast.subtitle}
               </span>
             </button>
           ))}