feat(backend,application,frontend,domain,web-server,app-tauri): bouton Redémarrer l'agent dans la barre supérieure des cellules — #317 (QA verte)

La cellule expose un bouton Redémarrer l'agent valable pour les trois
modes de présentation (headless, TUI native, CLI custom), sans jamais
prendre la présentation pour vérité runtime.

- Application: use case RestartCellAgentRuntime validant le binding
  exact cellule/runtime via les snapshots live (RestartRuntimeNotFound,
  ConflictAgentVisibleElsewhere, AgentNotBoundToCell) puis déléguant au
  scheduler self-restart existant (schedule_cell); CellAgentPresentation
  purement informationnelle.
- Backend/app-tauri/web-server: commande restart_cell_agent sur contrat
  DTO identique Tauri/HTTP, stop borné par timeout typé
  (RestartStopTimeout), relance préservant routage TUI natif, géométrie
  de cellule (node/rows/cols) et conversation; évenements domaine
  enrichis.
- Frontend: bouton dans la barre de cellule avec confirmation,
  overlay d'état Redémarrage…/échec (libellés par code d'erreur, Fermer/
  Réessayer), gardes d'identité de cellule et de restarts externes,
  gateway/mock/http adapters et ports alignés.
- Tests: dto_agents, workstate_actions, contrats web-server,
  LayoutGrid.cellControlsLayering, adapters agent/mock/http.

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

frontend/src/adapters/mock/mock.test.ts

@@ -6,7 +6,7 @@ import { describe, it, expect } from "vitest";
 
 import type { DomainEvent } from "@/domain";
 import type { Gateways } from "@/ports";
-import { createMockGateways, MockSystemGateway } from "./index";
+import { createMockGateways, MockAgentGateway, MockSystemGateway } from "./index";
 
 // Typechecking this assignment proves every mock implements its port.
 const gateways: Gateways = createMockGateways();
@@ -90,6 +90,42 @@ describe("MockSystemGateway", () => {
 });
 
 describe("other mock gateways", () => {
+  it("schedules a restart only for the agent runtime bound to the exact cell", async () => {
+    const agentGateway = new MockAgentGateway();
+    const agent = await agentGateway.createAgent("p1", {
+      name: "Worker",
+      profileId: "profile-1",
+    });
+    await agentGateway.launchAgent(
+      "p1",
+      agent.id,
+      { cwd: "/p1", rows: 24, cols: 80, nodeId: "node-1" },
+      () => {},
+    );
+
+    await expect(
+      agentGateway.restartCellAgentRuntime({
+        projectId: "p1",
+        nodeId: "node-1",
+        agentId: agent.id,
+        presentation: "tui",
+      }),
+    ).resolves.toMatchObject({
+      status: "scheduled",
+      agentId: agent.id,
+      nodeId: "node-1",
+      presentation: "tui",
+    });
+    await expect(
+      agentGateway.restartCellAgentRuntime({
+        projectId: "p1",
+        nodeId: "stale-node",
+        agentId: agent.id,
+        presentation: "tui",
+      }),
+    ).rejects.toMatchObject({ code: "AGENT_NOT_BOUND_TO_CELL" });
+  });
+
   it("project.createProject returns a project and listProjects reflects it", async () => {
     expect(await gateways.project.listProjects()).toEqual([]);
     const created = await gateways.project.createProject("n", "/root");