chore(deadcode): remove stale ACP testing aliases

src/acp/control-plane/manager.ts

@@ -32,4 +32,3 @@ export const testing = {
     ACP_SESSION_MANAGER_SINGLETON = manager as AcpSessionManager | null;
   },
 };
-export { testing as __testing };

src/acp/runtime/registry.ts

@@ -123,4 +123,3 @@ export const testing = {
     return resolveAcpRuntimeRegistryGlobalState();
   },
 };
-export { testing as __testing };