File variant.test.ts

packages/core/test/plugin/variant.test.ts:None–None

import { describe, expect } from "bun:test"
import { Catalog } from "@opencode-ai/core/catalog"
import { AppNodeBuilder } from "@opencode-ai/core/effect/app-node-builder"
import { LayerNode } from "@opencode-ai/core/effect/layer-node"