attrs_inline for images doesn't support % for width

[liborjelinek]

What version of myst-parser are you using?

4.0.0

What version dependencies are you using?

"sphinx==8.1.3",
"myst-parser==4.0.0",
"linkify-it-py==2.0.3",
"sphinx-design==0.6.1",
"sphinx_copybutton==0.5.2",
"sphinxcontrib.mermaid==0.9.2",

What operating system are you using?

Mac

Describe the Bug

The inline attributes extension, according to its docs, should support various units for image width and height. E.g.,

![](entities.png){w=50%}

should result in <img width="50%" ...>.

But the w=50% or width=50% aren't detected by attrs_inline, and a {..} string is printed after the image:

<img alt="" src="../_images/entities.png">{w=50%}

Also, unitless like {w=50} actually produce width="50px", which might be a bug too, or it should be documented.

Expected Behavior

No response

To Reproduce

No response