writeMidiFile: emit PART VOCALS / HARM1 / HARM2 / HARM3 tracks

[elicwhite]

Adds vocal-track emission to writeMidiFile. One MIDI track per vocal
part (vocals → PART VOCALS, harmony{1,2,3} → HARM{1,2,3}; HARM* not
PART HARM*, matching the convention used in the wild).

Phrase-marker emission is careful about YARG's CopyDownPhrases, which
at parse time copies HARM1's notePhrases onto HARM2/HARM3:

• PART VOCALS: notePhrases → 105 (player:2 → 106)
• HARM1: notePhrases → 105, staticLyricPhrases → 106
• HARM2: only staticLyricPhrases → 106 (note 105 comes from HARM1
  via CopyDown on re-parse — would double-count otherwise)
• HARM3: no phrase markers at all

Lyrics and notes are union'd across both phrase sets (note 105 and 106
can have different boundaries; emitting the union keeps all lyrics
that belong on the track). Zero-length vocal notes are preserved via
per-event seq tags so finalizeMidiTrack keeps noteOn immediately
before its matching noteOff.

Star power (MIDI 116) is suppressed on HARM2/HARM3 — CopyDown recreates
it from HARM1 on re-parse. Range shifts (MIDI 0) and lyric shifts (MIDI

1. are per-part for lossless round-trip, with fallback to the
   track-level arrays for the part that owns them (PART VOCALS, or HARM1
   when PART VOCALS is absent). Raw vocal-track text events (stance
   markers, facial anim triggers) are re-emitted verbatim so that
   stance-only tracks survive round-trip — YARG marks a VocalsPart
   non-empty iff it has phrases or text events.

Tests: 18 new cases covering track naming (PART VOCALS, HARM1/2/3 with
no PART HARM* prefix), phrase-marker routing per part, pitched/
percussion/out-of-range note emission, lyric union across phrase sets,
star power suppression on HARM2/3, range+lyric shifts, text events,
and round-trip through parseChartAndIni for both PART VOCALS and the
full harmony stack with CopyDown semantics preserved.

71 midi-writer tests, 415 total scan-chart tests passing.

[elicwhite]

Warning

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Learn more

• Add ChartDocument + writeChartFolder orchestrator #78 : 2 dependent PRs (#79 , #87 )
• Add same-format round-trip integration tests #77
• writeMidiFile: emit PART VOCALS / HARM1 / HARM2 / HARM3 tracks #76 👈 (View in Graphite)
• writeMidiFile: emit PART GUITAR / GHL instrument tracks #75
• writeMidiFile: emit PART DRUMS instrument tracks #74
• Add writeMidiFile() with TEMPO/EVENTS/unrecognized-track emission #72
• writeChartFile: emit instrument track sections #71
• Add writeChartFile() with Song/SyncTrack/Events/unrecognized-section emission #70
• Add writeIniFile() for song.ini emission #69
• Add createEmptyChart() counterpart to parseChartAndIni #68
• Add shared File type in interfaces.ts #86
• master

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