File usage.test.ts

packages/opencode/test/acp/usage.test.ts:None–None

import { describe, expect, test } from "bun:test"
import type { SessionNotification } from "@agentclientprotocol/sdk"
import { LayerNode } from "@opencode-ai/core/effect/layer-node"
import { ProviderV2 } from "@opencode-ai/core/provider"