Refactor LLM route-first provider API (#28523)

packages/llm/src/provider.ts

@@ -1,14 +1,20 @@
-import type { RouteModelInput } from "./route/client"
-import type { ModelID, ModelRef, ProviderID } from "./schema"
+import type { RouteDefaultsInput } from "./route/client"
+import type { Model, ModelID, ProviderID } from "./schema"
 
-export type ModelOptions = Omit<RouteModelInput, "id">
+export type ModelOptions = RouteDefaultsInput
 
+/**
+ * Advanced structural provider definition helper. Built-in providers should
+ * prefer explicit `configure(options).model(id)` facades so deployment config is
+ * chosen before model selection. The optional `apis` map remains for external
+ * structural providers that expose multiple route selectors behind one provider.
+ */
 export type ModelFactory<Options extends ModelOptions = ModelOptions> = (
   id: string | ModelID,
   options?: Options,
-) => ModelRef
+) => Model
 
-type AnyModelFactory = (...args: never[]) => ModelRef
+type AnyModelFactory = (...args: never[]) => Model
 
 export interface Definition<Factory extends AnyModelFactory = ModelFactory> {
   readonly id: ProviderID
@@ -18,8 +24,8 @@ export interface Definition<Factory extends AnyModelFactory = ModelFactory> {
 
 type DefinitionShape = {
   readonly id: ProviderID
-  readonly model: (...args: never[]) => ModelRef
-  readonly apis?: Record<string, (...args: never[]) => ModelRef>
+  readonly model: (...args: never[]) => Model
+  readonly apis?: Record<string, (...args: never[]) => Model>
 }
 
 type NoExtraFields<Input, Shape> = Input & Record<Exclude<keyof Input, keyof Shape>, never>