\enclose{roundedbox} mis-sized and vertically misaligned for \frac / tall content (regression or incomplete fix of #1697)

[kevin1078]

Description

\enclose{roundedbox}{…} does not correctly wrap tall math (especially \frac with nested \sqrt). The border is not vertically centered, and the box size does not match the laid-out content.
Reproducible with convertLatexToMarkup() and <math-field> on MathLive 0.110.0 (npm). Same LaTeX looks correct in MathJax (MathML menclose).

Steps to reproduce

Paste into the MathLive demo or any math-field:

\enclose{roundedbox}[shadow="none",1px dotted #cd0030]{\frac{x^2+y^2}{\sqrt{x^2+y^2}}}
Simpler case:
\enclose{roundedbox}[mathcolor=red]{\frac{a}{b}}

More cases:
\displaylines{\enclose{updiagonalstrike roundedbox}[mathbackground="#fbc0bd",shadow="none", solid red]{x=0}\\
 \enclose{circle}[mathbackground="#fbc0bd",shadow="none", solid currentColor]{\frac{1}{x}}\\
 \enclose{roundedbox}[shadow="none",1px dotted #cd0030]{\frac{x^2+y^2}{\sqrt{x^2+y^2}}}\\
 }

Actual behavior
Content sits too high inside the box (top-aligned).
Border box is wider than the inner math box (default fboxsep padding ≈ 0.3em).
For the fraction+sqrt example (0.110.0): host 3.08em tall / 7.92em wide; body 2.49em tall; .ML__notation ~8.52em wide.
Expected behavior
Content centered in the border; border tightly wraps content + uniform padding.

Technical notes
In EncloseAtom.render (0.110.0): .ML__notation is position:absolute; top:0; body child is not vertically centered; default padding from fboxsep when padding is unset.

Partial workaround: padding="0" — reduces horizontal overflow, does not fix vertical centering for \frac.

Related
#1697 (\enclose + padding + \frac, closed but fraction cases still look wrong)
#2919 (GenfracAtom / tall content sizing since 0.108)
Environment
MathLive 0.110.0
Windows 10

[kevin1078]