Update to new GraphQL incremental delivery format

[dantrain]

Summary

Updates to support the new GraphQL incremental delivery response format as specified in the draft @defer/@stream proposal. This is a breaking change requiring updates to client-side code.

Changes

• Upgrade graphql to 17.0.0-alpha.9 - Uses native experimentalExecuteIncrementally instead of @graphql-tools/executor
• New response format - Handle pending/incremental/completed arrays with ID-based tracking (replaces direct path on incremental items)
• Updated Accept header - incrementalSpec=v0.2 replaces deferSpec=20220824
• New processMultipartResponse utility - Exported from @remix-relay/react for client-side multipart processing
• Relay normalization fix - Merge parent id into deferred fragments for proper store normalization

Migration

Replace custom multipart processing with the new utility:

import { processMultipartResponse } from "@remix-relay/react";

const parts = await meros(response);
for await (const payload of processMultipartResponse(parts)) {
  sink.next(payload);
}

Update Accept header to multipart/mixed; incrementalSpec=v0.2, application/json

References

• Incremental Delivery spec draft graphql/graphql-spec#1110
• https://github.com/graphql/defer-stream-wg
• Reference implementation of defer and stream spec graphql/graphql-js#3659
• https://github.com/graphql/graphql-over-http/blob/main/rfcs/IncrementalDelivery.md