Reference links with a definition in another block are not resolved, and loose lists render as tight #665

Bug Description

Splitting the message into blocks and parsing each block on its own changes the result for two common markdown shapes, compared with parsing the whole message (what react-markdown does with the same remark-gfm setup):

1. A reference-style link whose definition is in another block is not resolved, so users see the raw [the docs][1] text.
2. A loose list (blank lines between items) is rendered as a tight list: the items lose their <p> wrappers.

Footnotes defined in a later paragraph do work, so I think only reference definitions and list looseness are affected.

Steps to Reproduce

Render these with <Streamdown parseIncompleteMarkdown={false}> and with <ReactMarkdown remarkPlugins={[remarkGfm]}>:

See [the docs][1] for details.

More text here.

[1]: https://example.com/docs

- one

- two

- three

Expected Behavior

The same structure as a whole-document parse: a link to https://example.com/docs, and list items wrapped in <p> (as react-markdown renders them).

Actual Behavior

• <p>See [the docs][1] for details.</p>, no link, and the definition line is dropped.
• <li>one</li><li>two</li><li>three</li> with no paragraph wrappers.

Code Sample

import { renderToStaticMarkup } from 'react-dom/server'
import ReactMarkdown from 'react-markdown'
import remarkGfm from 'remark-gfm'
import { Streamdown } from 'streamdown'

const md = 'See [the docs][1] for details.\n\nMore text here.\n\n[1]: https://example.com/docs\n'
console.log(renderToStaticMarkup(<ReactMarkdown remarkPlugins={[remarkGfm]}>{md}</ReactMarkdown>)) // link resolved
console.log(renderToStaticMarkup(<Streamdown parseIncompleteMarkdown={false}>{md}</Streamdown>))    // raw [the docs][1]

Streamdown Version

2.7.0

React Version

19.3.0

Node.js Version

24.20.0

Browser(s)

Reproduced with server rendering (renderToStaticMarkup), so not browser specific.

Operating System

macOS