refactor(core): nest model api id (#30603)

packages/core/test/plugin/provider-xai.test.ts

@@ -12,8 +12,8 @@ const it = testEffect(PluginV2.locationLayer.pipe(Layer.provide(EventV2.defaultL
 
 const model = new ModelV2.Info({
   ...ModelV2.Info.empty(ProviderV2.ID.make("xai"), ModelV2.ID.make("grok-4")),
-  apiID: ModelV2.ID.make("grok-4"),
   api: {
+    id: ModelV2.ID.make("grok-4"),
     type: "aisdk",
     package: "@ai-sdk/xai",
   },
@@ -72,7 +72,7 @@ describe("XAIPlugin", () => {
     }),
   )
 
-  it.effect("uses responses with the model apiID for xAI language models", () =>
+  it.effect("uses responses with the model api.id for xAI language models", () =>
     Effect.gen(function* () {
       const plugin = yield* PluginV2.Service
       const calls: string[] = []
@@ -81,7 +81,7 @@ describe("XAIPlugin", () => {
       const result = yield* plugin.trigger(
         "aisdk.language",
         {
-          model: new ModelV2.Info({ ...model, id: ModelV2.ID.make("alias"), apiID: ModelV2.ID.make("grok-4") }),
+          model: new ModelV2.Info({ ...model, id: ModelV2.ID.make("alias") }),
           sdk: fakeSelectorSdk(calls),
           options: {},
         },