refactor(opencode): extract session LLM request prep (anomalyco#28560)

Author: kitlangton

packages/opencode/src/session/llm.ts

@@ -1,5 +1,4 @@
 import { Provider } from "@/provider/provider"
-import { serviceUse } from "@/effect/service-use"
 import * as Log from "@opencode-ai/core/util/log"
 import { Context, Effect, Layer } from "effect"
 import * as Stream from "effect/Stream"
@@ -55,8 +54,6 @@ export interface Interface {
 
 export class Service extends Context.Service<Service, Interface>()("@opencode/LLM") {}
 
-export const use = serviceUse(Service)
-
 const live: Layer.Layer<
   Service,
   never,
@@ -223,6 +220,8 @@ const live: Layer.Layer<
           provider: item,
           auth: info,
           llmClient,
+          isOpenaiOauth: prepared.isOpenaiOauth,
+          system: prepared.system,
           messages: prepared.messages,
           tools: prepared.tools,
           toolChoice: input.toolChoice,