Implement PagedAsyncIterableIterator for paginated list operations

[daviburg]

Context

All list operations in the Node SDK return Promise<TListResult> directly (e.g., Promise<SubscriptionListResult>). The .NET SDK returns AsyncPageable<T> via ConnectorClientBase.CreatePageable<TPage, TItem>(), which automatically follows nextLink URLs across pages and yields items as an async enumerable.

Currently the Node SDK has no pagination at all — callers receive the first page and must manually implement nextLink following.

Parity gap

Aspect	.NET SDK	Node SDK
Return type for lists	AsyncPageable<T> (lazy, follows nextLink)	Promise<TListResult> (first page only)
Caller experience	await foreach (var item in client.ListAsync())	Manual nextLink loop
nextLink validation	SSRF-protected in ResolveUrl()	N/A (not implemented)
Azure SDK guideline	AsyncPageable<T> / IPageable<T>	PagedAsyncIterableIterator<T> required

Proposed change

List operations should return PagedAsyncIterableIterator<T> from @azure/core-paging:

import { PagedAsyncIterableIterator } from "@azure/core-paging";

// e.g., in ArmClient
public listSubscriptions(options?: ListSubscriptionsOptions): PagedAsyncIterableIterator<Subscription>

This requires:

1. Generator changes in CodefulSdkGenerator to emit PagedAsyncIterableIterator return types
2. Adding @azure/core-paging as a dependency
3. Implementing nextLink following in ConnectorClientBase with SSRF protection (see companion SSRF issue)

This is a breaking change to all list method signatures and return types.

Azure SDK guideline

• DO return PagedAsyncIterableIterator for paginated operations