refactor(opencode): remove core service layer exports (#34518)

packages/opencode/src/acp/session.ts

@@ -94,7 +94,7 @@ export class Service extends Context.Service<Service, Interface>()("@opencode/AC
 
 type State = Map<string, Info>
 
-export const layer = Layer.effect(
+const layer = Layer.effect(
   Service,
   Effect.gen(function* () {
     const sessions = yield* Ref.make<State>(new Map())
@@ -201,8 +201,6 @@ export const layer = Layer.effect(
   }),
 )
 
-export const defaultLayer = layer
-
 export const node = LayerNode.make({ service: Service, layer, deps: [] })
 
 function makeSession(input: StoreInput): Info {