feat(agents): role orchestrateur du contexte global expose et configurable par agent — isOrchestrator distinct des permissions MCP, DTO update_project_orchestrator (terminologie wire legacy conservee), refus idea_context_update explicite avec writer effectif + orientation idea_context_propose, surface AgentsPanel + adaptateurs frontend — #276 (QA verte: cargo fmt/check, tests cibles application/app-tauri/infrastructure/backend, npm typecheck, 69/69 tests frontend agents/adapters)

frontend/src/adapters/http/agentGateway.test.ts

@@ -141,6 +141,26 @@ describe("HttpAgentGateway WS round-trip (B6 frames)", () => {
     });
   });
 
+  it("updates the project orchestrator through the dedicated request DTO", async () => {
+    const response = { orchestratorAgentId: "agent-2" };
+    const { gw, calls } = httpAgentGateway(async () => ({
+      ok: true,
+      status: 200,
+      json: async () => response,
+      text: async () => JSON.stringify(response),
+    }));
+
+    await expect(
+      gw.updateProjectOrchestrator("proj-1", "agent-2"),
+    ).resolves.toEqual(response);
+
+    const init = calls[0].init as { body: string };
+    expect(JSON.parse(init.body)).toEqual({
+      command: "update_project_orchestrator",
+      args: { request: { projectId: "proj-1", agentId: "agent-2" } },
+    });
+  });
+
   it("launch → attached: conforming agent.launch frame, assignedConversationId consumed", async () => {
     const { gw, sockets } = gateway();
     const chunks: Uint8Array[] = [];