Export aisdk (#1058)

# why

Easier to use for Custom LLM Clients and keep users up to date with our
aisdk file

# what changed

added export of aisdk to lib/index.ts

# test plan

build local stagehand, import local AISdkClient, run Azure Stagehand
session

Author: chrisreadsf

lib/index.ts

@@ -1028,4 +1028,5 @@ export * from "../types/stagehand";
 export * from "../types/stagehandApiErrors";
 export * from "../types/stagehandErrors";
 export * from "./llm/LLMClient";
+export * from "./llm/aisdk";
 export { connectToMCPServer };