Torn paper effect on a Tcolorbox

I tried to set-up a tcolorbox with a teared paper effect on the bottom side. I looked at these questions and answers:

• Torn page effect
• Torn paper: matching up the torn edges

And, I finally ended with the following code:

documentclass{article}

usepackage{lipsum}
usepackage{tikz}
usetikzlibrary{decorations.pathmorphing,shadows.blur,shadings}
%pgfmathsetseed{1} % To have predictable results

usepackage[most]{tcolorbox}

% Define a background layer, in which the parchment shape is drawn
pgfdeclarelayer{background}
pgfsetlayers{background,main}

% This is the base for the fractal decoration. It takes a random point
% between the start and end, and raises it a random amount, thus
% transforming a segment into two, connected at that raised point This
% decoration can be applied again to each one of the resulting
% segments and so on, in a similar way of a Koch snowflake.
pgfdeclaredecoration{irregular fractal line}{init}
{
  state{init}[width=pgfdecoratedinputsegmentremainingdistance]
  {
    pgfpathlineto{%
      pgfpoint{random * pgfdecoratedinputsegmentremainingdistance}{%
        (random * pgfdecorationsegmentamplitude - 0.02) *
         pgfdecoratedinputsegmentremainingdistance}}
    pgfpathlineto{pgfpoint{pgfdecoratedinputsegmentremainingdistance}{0pt}}
  }
}

% Define paper style
tikzset{
  paper/.style={%
    draw=black!10,
    blur shadow,
    path picture={%
      node at (path picture bounding box.center) {
        includegraphics[width=linewidth]{note-background.png}
      };
    }
  },
  irregular border/.style={%
    decoration={irregular fractal line, amplitude=0.2},
    decorate,
  },
  ragged border/.style={%
    decoration={random steps, segment length=7mm, amplitude=2mm},
    decorate,
  }
}

newtcolorbox{tcbnote}{%
  % enhanced jigsaw, <-- Beware, This rendering engine let the
  %                      frame appear on some PDF viewers
  empty, % Better use this rendering engine to avoid the bug
  interior code={%
    begin{pgfonlayer}{background}  % Draw the shape behind
      fill[paper] % recursively decorate the bottom border
      decorate[irregular border]{%
        decorate{decorate{decorate{decorate[ragged border]{
                ($(interior.south east) - (0, random * 5mm)$) --
                ($(interior.south west) - (0, random * 5mm)$)
              }
            }
          }
        }
      }
      -- (interior.north west) -- (interior.north east) -- cycle;
    end{pgfonlayer}
  },
  sharp corners,
  boxrule=0pt,
  left=5pt,
  right=5pt,
  top=5pt,
  bottom=1em,
}

%% TColorBox Note environment
newlengthsavedparindent
setlengthsavedparindentparindent
newenvironment{note}[1]{%
  begin{tcbnote}{}
    setlengthparindent{savedparindent}
    begin{center}
      sffamilybfseriesLARGE #1
    end{center}par
  }{%
  end{tcbnote}
}


begin{document}
pagestyle{empty}

begin{note}{Note Title}
  lipsum[1-2]
end{note}

end{document}

The background image used here is the following.

The final result is as follow.

This fit perfectly my initial expectations, but I am not really satisfied with the LaTeX code I came with for several reasons (see below). So, I am asking for a few hints and advises to improve it.

My main problems are:

• I did not manage to use the native title of the tcolorbox because I did find how to expand the background to continuously cover also the first part of the box;

• [Solved thanks to Teepeemm] The parindent variable seems to be reset to zero in this environment and I do not see why this happen. I did find a workaround by saving parindent and restoring it inside the environment. But this is just a bad hack.

• Any other improvement ideas are more than welcome !

documentclass{article}

usepackage{lipsum}
usepackage{tikz}
usetikzlibrary{decorations.pathmorphing,shadows.blur,shadings}
%pgfmathsetseed{1} % To have predictable results

usepackage[most]{tcolorbox}

% Define a background layer, in which the parchment shape is drawn
pgfdeclarelayer{background}
pgfsetlayers{background,main}

% This is the base for the fractal decoration. It takes a random point
% between the start and end, and raises it a random amount, thus
% transforming a segment into two, connected at that raised point This
% decoration can be applied again to each one of the resulting
% segments and so on, in a similar way of a Koch snowflake.
pgfdeclaredecoration{irregular fractal line}{init}
{
  state{init}[width=pgfdecoratedinputsegmentremainingdistance]
  {
    pgfpathlineto{%
      pgfpoint{random * pgfdecoratedinputsegmentremainingdistance}{%
        (random * pgfdecorationsegmentamplitude - 0.02) *
         pgfdecoratedinputsegmentremainingdistance}}
    pgfpathlineto{pgfpoint{pgfdecoratedinputsegmentremainingdistance}{0pt}}
  }
}

% Define paper style
tikzset{
  paper/.style={%
    draw=black!10,
    blur shadow,
    path picture={%
      node at (path picture bounding box.center) {
        includegraphics[width=linewidth]{note-background.png}
      };
    }
  },
  irregular border/.style={%
    decoration={irregular fractal line, amplitude=0.2},
    decorate,
  },
  ragged border/.style={%
    decoration={random steps, segment length=7mm, amplitude=2mm},
    decorate,
  }
}

newtcolorbox{tcbnote}[2][]{%
  % enhanced jigsaw, <-- Beware, This rendering engine let the
  %                      frame appear on some PDF viewers
  empty, % Better use this rendering engine to avoid the bug
  interior code={%
    begin{pgfonlayer}{background}  % Draw the shape behind
      fill[paper] % recursively decorate the bottom border
      decorate[irregular border]{%
        decorate{decorate{decorate{decorate[ragged border]{
                ($(interior.south east) - (0, random * 5mm)$) --
                ($(interior.south west) - (0, random * 5mm)$)
              }
            }
          }
        }
      }
      -- (interior.north west) -- (interior.north east) -- cycle;
    end{pgfonlayer}
  },
  sharp corners,
  boxrule=0pt,
  left=5pt,
  right=5pt,
  top=5pt,
  bottom=1em,
  fonttitle=sffamilybfseriesLARGE,
  attach boxed title to top center={yshift*=-tcboxedtitleheight},
  coltitle=black,
  before upper={setlengthparindent{savedparindent}},
  title=#2,
  #1
}

%% TColorBox Note environment
newlengthsavedparindent
setlengthsavedparindentparindent

begin{document}
pagestyle{empty}

begin{tcbnote}{Note Title}
  lipsum[1-2]
end{tcbnote}

end{document}