Fix chord annotations and add multivoice spine splits
This PR corrects annotation errors found in the synthetic dataset, mirroring the same fixes applied to the original dataset.
LO:TX chord annotation fixes
In the synthetic variants of the same affected pages, chord symbols were incorrectly encoded as Humdrum local text layout annotations (!LO:TX:a:t=CHORD) rather than in the **mxhm harmony spine.
Before:
!LO:TX:a:t=Bmi7 !
2b_ .
After:
2b_ B:min7
Affected pages and corrections (same as original dataset, applied across all synthetic variants — _synjazz, _synclassical, etc.):
Page System Encoded text Corrected **mxhm
slow-hot-wind 4 Bmi7 B:min7
slow-hot-wind 4 E7-9 E:7(b9)
slow-hot-wind 5 Dmi9 D:min9
moon-river 2 Eb(#11) Eb:maj(#11)
phase-dance 1,3,5 Bb^(#11) Bb:maj(#11)
how-deep-is-the-ocean_v1 4 G +/B G:aug/B
four 7 Ebm Eb:min
st-thomas 2 Em7(b5) Em:min7(b5)
st-thomas 2 Ab7(#5) Ab:7(#5)
mamacita 3 C7(#9) C:7(#9)
mamacita 3 Bb7(#9) Bb:7(#9)
speak-no-evil_v1 2 A-7b5 A:hdim7
oleo 2 Gmu7 G:min7
miyako 3 amj7 A:maj7
mood-indigo 3 Eb+7 Eb:aug7
sophisticated-lady 3,4 D7(b9), F7(b9) D:7(b9), F:7(b9)
last-train-home 1,4 F7sus4, Eb6#11 F:sus4(7), Eb:6(#11)
happy-holiday 7 Bb6 Bb:6
moment-to-moment 0 Am A:min
Non-chord !LO:TX lines (tempo markings, navigation markers, etc.) were left untouched.
Misplaced chord annotation — phase-dance (sys 1)
For all synthetic variants of phase-dance, Bb:maj(#11) was being placed on the wrong note (beat 1 of measure 2, 8cc] 8ee]) due to the !LO:TX line being at a non-adjacent position. Corrected to beat 1 of measure 1 (4ccni 4ffni).
Cleared erroneous chords from four system 6
Same as original: system 6 of four contained chord annotations in **mxhm with no corresponding image content. All chord values cleared to ..
All changes are applied consistently to both the system-level **kern fields and the full-page encodings['**kern'] field.