code block not working. only fenced code block works.

[tonny008]

Bug Description

code block indent with four spaces or one tab is not working.

Steps to Reproduce

     this is 
     code block
     indent

this is 
code block
indent

Expected Behavior

render as code block

this is 
code block
indent

Actual Behavior

render as paragraph

this is code block indent

Code Sample

Streamdown Version

1.6.10

React Version

19

Node.js Version

No response

Browser(s)

No response

Operating System

None

Additional Context

No response