Automatically adjust tcolobox to size of minted line numbers

Try this not-elegant-enough attempt.

Some key ideas:

• Assign a unique number to each Verbatim environment by using new counter verbatim@cnt.
• Get the ending code line number per Verbatim env (stored in counter FancyVerbLine), convert it to a dimension, and make it linked with the unique env number.
• Write this relation to aux file, which will be read at the second compilation.
• In each customized tcolorbox env, use current Verbatim env number to retrieve the corresponding dimension, then use it to set both left padding /tcb/left and the offset of the background color of line numbers drawn in `/tcb/overlay.

documentclass[11pt,letterpaper]{article}
usepackage[most, minted]{tcolorbox}

newcounter{verbatim@cnt}

makeatletter
AtEndEnvironment{Verbatim}{%
  stepcounter{verbatim@cnt}%
  protected@write@auxout{}{%
    globalprotect@namedef{verbatim@numwidth@thec@verbatim@cnt}{%
      ifnumc@FancyVerbLine>999
        7.5mm%
      elseifnumc@FancyVerbLine>99
        6mm%
      else
        4mm%
      fifi
    }%
  }%
}

defminted@auto@numwidth#1{%
  ifcsname verbatim@numwidth@thenumexprc@verbatim@cnt#1relaxendcsname
    csname verbatim@numwidth@thenumexprc@verbatim@cnt#1relaxendcsname
  else
    4mm%
  fi
}
makeatother

makeatletter
newtcblisting{myminted}[2][]{%
    listing engine=minted,
    minted language=#2,
    listing only,
    breakable,
    enhanced,
    minted options = {
        linenos, 
        breaklines=true, 
        breakbefore=., 
        fontsize=footnotesize, 
        numbersep=2mm
    },
    overlay={%
        begin{tcbclipinterior}
            fill[gray!25] (frame.south west) rectangle ([xshift=dimexprminted@auto@numwidth{}relax]frame.north west);
        end{tcbclipinterior}
    },
    % in "left", c@verbatim@cnt is not stepped yet, hence the argument "+1"
    left=dimexprminted@auto@numwidth{+1}relax,
    #1   
}
makeatother

%usepackage{unravel}
providecommandunravel[1]{#1}
providecommandunravelsetup[1]{}
unravelsetup{max-action=1000, max-input=1000, max-output=100}


begin{document}

begin{myminted}[minted options app={firstnumber=8}]{c}
#include <stdio.h>

void main ()
{
    printf("hello world");
}
end{myminted}

begin{myminted}[minted options app={firstnumber=98}]{c}
#include <stdio.h>

void main ()
{
    printf("hello world");
}
end{myminted}

begin{myminted}[minted options app={firstnumber=998}]{c}
#include <stdio.h>

void main ()
{
    printf("hello world");
}
end{myminted}

end{document}