feat(mcp,orchestrator,frontend): tool idea_restart_self, redemarrage autonome d'un agent — #288 (tool core self-only via requester MCP handshake, retour immediat {restartId, status: scheduled} puis orchestration detachee: snapshot reprise, stop PTY/structured, liberation Busy/mailbox, relance LaunchAgent meme conversation_id fresh_start=false, injection interne invisible; events domain/wire agentRestartRequested/PhaseChanged/Completed/Failed phases stopping/releasingInput/launching/resuming; CLI custom: separateurs exacts redemarrage de l'agent + etat termine/echoue, deduplication (restartId, event), verrouillage composer; TUI native: overlay AgentRestartOverlay sans injection xterm, progress/annonces projetes jusqu'a idle; QA verte: mcp_server restart_self 1/1, restart-self 3/3, backend self_restart_contract + events wire 2/2, frontend 3 suites 92/92, npm build, cargo check --workspace, fmt --check, diff --check; reserves hors perimetre: web-server 103/110 fixture PTY preexistante, 34 echecs npm test globaux listProjectSettings/web hors #288; scripts/ hors perimetre)

frontend/src/features/layout/LayoutGrid.cellControlsLayering.test.tsx

@@ -367,4 +367,26 @@ describe("LayoutGrid — ticket #48 cell control layering", () => {
       );
     },
   );
+
+  it("gives the native TUI restart overlay priority over other cell veils", async () => {
+    const setup = await makeSplitAgentGrid();
+    renderGrid(setup.gateways);
+    await flush();
+
+    act(() => {
+      setup.system.emit(busy(setup.agentId, true));
+      setup.system.emit({
+        type: "agentRestartRequested",
+        agentId: setup.agentId,
+        restartId: "restart-1",
+        reason: null,
+      });
+    });
+
+    const overlay = await screen.findByTestId("agent-restart-overlay");
+    expect(overlay.className).toContain("z-[4]");
+    expect(screen.queryByTestId("target-announcements-overlay")).toBeNull();
+    expect(screen.queryByText("------- redemarrage de l'agent -------")).toBeNull();
+    expect(controlsFor(setup.bId).controls.style.zIndex).toBe("5");
+  });
 });