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>

crates/app-tauri/tests/dto_agents.rs

@@ -741,3 +741,53 @@ fn stop_live_agent_response_serialises_camelcase_with_kind() {
     assert_eq!(v["alreadyStopped"], false);
     assert!(v.get("session_id").is_none());
 }
+
+#[test]
+fn restart_cell_agent_request_deserialises_all_presentations() {
+    use app_tauri_lib::dto::{CellAgentPresentationDto, RestartCellAgentRuntimeRequestDto};
+
+    for (wire, expected) in [
+        ("headless", CellAgentPresentationDto::Headless),
+        ("tui", CellAgentPresentationDto::Tui),
+        ("customCli", CellAgentPresentationDto::CustomCli),
+        ("unknown", CellAgentPresentationDto::Unknown),
+    ] {
+        let raw = json!({
+            "projectId": Uuid::from_u128(1).to_string(),
+            "nodeId": Uuid::from_u128(2).to_string(),
+            "agentId": Uuid::from_u128(3).to_string(),
+            "presentation": wire,
+            "layoutId": Uuid::from_u128(4).to_string()
+        });
+        let dto: RestartCellAgentRuntimeRequestDto = serde_json::from_value(raw).unwrap();
+        assert_eq!(dto.presentation, expected);
+        assert_eq!(dto.layout_id, Some(Uuid::from_u128(4).to_string()));
+    }
+}
+
+#[test]
+fn restart_cell_agent_response_uses_restart_event_correlation_contract() {
+    use app_tauri_lib::dto::RestartCellAgentRuntimeResponseDto;
+    use application::{CellAgentPresentation, LiveSessionKind, RestartCellAgentRuntimeOutput};
+
+    let agent = AgentId::from_uuid(Uuid::from_u128(11));
+    let node = NodeId::from_uuid(Uuid::from_u128(12));
+    let layout = domain::LayoutId::from_uuid(Uuid::from_u128(13));
+    let dto = RestartCellAgentRuntimeResponseDto::from(RestartCellAgentRuntimeOutput {
+        restart_id: "restart-317".to_owned(),
+        agent_id: agent,
+        node_id: node,
+        kind: LiveSessionKind::Structured,
+        presentation: CellAgentPresentation::CustomCli,
+        layout_id: Some(layout),
+    });
+
+    let value = serde_json::to_value(dto).unwrap();
+    assert_eq!(value["restartId"], "restart-317");
+    assert_eq!(value["status"], "scheduled");
+    assert_eq!(value["agentId"], agent.to_string());
+    assert_eq!(value["nodeId"], node.to_string());
+    assert_eq!(value["kind"], "structured");
+    assert_eq!(value["presentation"], "customCli");
+    assert_eq!(value["layoutId"], layout.to_string());
+}