\tocItem within \score block, using header properties

[Joel C. Salomon]

The requirement that `\tocItem` is either outside the `\score` block
or within a music variable is making it awkward for me to keep it near
where the score `\header` block defines the piece title.  And I have
entirely failed to figure out a way to re-use the piece title.

Minimal example below, showing different ways I've tried.

Is there a cleaner way to accomplish this?

—Joel

\version "2.23.80"

upperI = \relative c' {
  \tocItem \markup "Piece Title" % works, but is an awkward place
  c4 d e f }
lowerI = \relative c {\clef bass f e d c }

scoreI = \score {
  \header {
    piece = "Piece Title"
  }
  \new PianoStaff <<
  %  \tocItem \markup \fromproperty #'header:piece % doesn't work
  %  \tocItem \markup "Piece Title" % works, but creates extra staff
    \new Staff = "upper" \upperI
    \new Staff = "lower" \lowerI
  >>
}

\book {
  \markuplist \table-of-contents
  %  \tocItem \markup "Piece Title" % breaks locality
  \scoreI
}