refactor(opencode): fetch remote config with http client (#28661)

packages/opencode/test/agent/plugin-agent-regression.test.ts

@@ -1,6 +1,7 @@
 import { expect } from "bun:test"
 import { AppFileSystem } from "@opencode-ai/core/filesystem"
 import { Effect, Layer } from "effect"
+import { FetchHttpClient } from "effect/unstable/http"
 import path from "path"
 import { pathToFileURL } from "url"
 import { Agent } from "../../src/agent/agent"
@@ -29,6 +30,7 @@ const configLayer = Config.layer.pipe(
   Layer.provide(AuthTest.empty),
   Layer.provide(AccountTest.empty),
   Layer.provide(NpmTest.noop),
+  Layer.provide(FetchHttpClient.layer),
 )
 const pluginLayer = Plugin.layer.pipe(
   Layer.provide(Bus.layer),