Documentation mismatch: useUIStream expects JSONL patch format but API route example outputs plain JSON

Problem

The documentation for API route setup in AI SDK Integration and Streaming shows a simple example that directly returns result.textStream:

// From docs (https://json-render.dev/docs/ai-sdk)
export async function POST(req: Request) {
  const { prompt } = await req.json();
  const systemPrompt = generateCatalogPrompt(catalog);

  const result = streamText({
    model: 'anthropic/claude-haiku-4.5',
    system: systemPrompt,
    prompt,
  });

  return new Response(result.textStream, {
    headers: { 'Content-Type': 'text/plain; charset=utf-8' },
  });
}

I followed this pattern with a minor difference (using @ai-sdk/openai provider instead of AI Gateway string format):

// My implementation
import { streamText } from 'ai';
import { openai } from '@ai-sdk/openai';
import { generateCatalogPrompt } from '@json-render/core';
import { catalog } from '@/lib/catalog';

export async function POST(req: Request) {
  const { prompt } = await req.json();
  const systemPrompt = generateCatalogPrompt(catalog);

  const result = streamText({
    model: openai('gpt-5.2'),  // Using @ai-sdk/openai provider
    system: systemPrompt,
    prompt,
  });

  return new Response(result.textStream, {
    headers: { 'Content-Type': 'text/plain; charset=utf-8' },
  });
}

Actual Output

The AI model outputs nested JSON (not JSONL patch format):

{
  "type": "Card",
  "props": {
    "title": "Claim Form"
  },
  "children": [
    {
      "type": "Text",
      "props": {
        "text": "Please review your details and submit your claim."
      }
    },
    {
      "type": "Button",
      "props": {
        "text": "Submit Claim",
        "action": {
          "type": "submit"
        }
      }
    }
  ]
}

Expected Format by useUIStream

However, looking at the source code of useUIStream, it expects JSONL patch format (one JSON patch per line):

{"op":"set","path":"/root","value":"el-1"}
{"op":"add","path":"/elements/el-1","value":{"key":"el-1","type":"Card","props":{...}}}
{"op":"add","path":"/elements/el-2","value":{"key":"el-2","type":"Text","props":{...},"parentKey":"el-1"}}

The hook parses each line as a patch operation:

// From @json-render/react source
const lines = buffer.split("\n");
for (const line of lines) {
  const patch = parsePatchLine(line);
  if (patch) {
    currentTree = applyPatch(currentTree, patch);
  }
}

Result

When following the documentation example:

1. AI model outputs nested JSON (as shown above)
2. useUIStream tries to parse each line as a JSON patch
3. Parsing fails because the format doesn't match
4. tree remains { root: "", elements: {} } (empty)
5. Nothing renders on the page

Environment

• @json-render/core: ^0.3.0
• @json-render/react: ^0.2.0
• ai: ^6.0.44
• @ai-sdk/openai: latest

Compare the API route examples in the linked AI SDK Integration and Streaming documentation with the useUIStream parsing behavior in @json-render/react, especially parsePatchLine. Update the examples so the documented response format matches what the hook consumes, then verify that the resulting stream produces a rendered tree rather than an empty one.