fix: Validate every paginated request like the original request (#1009)

* fix: Validate every paginated request like the original request

The paginator rebuilt each page request with only the pathname, method,
response key, and data, dropping the request parameters and validation
configuration, so required parameter checks were skipped for every
paginated fetch including the first page. A cursor was also dropped
entirely when the original request had no params or body.

Build each page through a new SeamHttpRequest.withPageCursor, which
copies the entire request configuration and merges the page cursor into
the params or body chosen by the request method. New configuration
fields now travel to page requests automatically instead of being
hand-copied in the paginator.

Co-Authored-By: Claude <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B8xeJm2Hd923k8uo6eoFd2

* Apply suggestion from @razor-x

* docs: Trim the withPageCursor doc

Co-Authored-By: Claude <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01B8xeJm2Hd923k8uo6eoFd2

---------

Co-authored-by: Claude <noreply@anthropic.com>

Author: razor-x

codegen/layouts/partials/route-class-methods.hbs

@@ -100,7 +100,7 @@ static fromPersonalAccessToken(
 createPaginator<const TResponse, const TResponseKey extends keyof TResponse>(
   request: SeamPaginatedRequest<TResponse, TResponseKey>,
 ): SeamPaginator<TResponse, TResponseKey> {
-  return new SeamPaginator<TResponse, TResponseKey>(this, request)
+  return new SeamPaginator<TResponse, TResponseKey>(request)
 }
 
 async updateClientSessionToken(