scoreview-engine v4.7.7-engine.1

release v4.7.7-engine.1

MuseScore 4.7.7 (b750c43) (#46, closes #47). The only upstream file this
tree carries a copy of that moved is share/instruments/instruments.xml:
"Acoustic Bass" is now an ambiguous entry with pizzicato, arco and tremolo
channels, a separate acoustic-bass-guitar instrument was added, and the
contrabass pPitchRange widened to 34-74. Re-copied verbatim, lock re-pinned.

Corpus gate: 570/570 scores convert, no regressions, all 8 native waivers
still fire. The wasm gate passes with the same 11 libm-noise waivers.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>