A lullaby lane reusing the real AC marimba synth (pop/marimba/synths/marimba.mjs). lib/core.mjs renders events -> stereo mix + soft reverb + a constant 528Hz Solfeggio healing drone (sub-octave, slow breath) -> gentle mp3 master. lib/marimbaba.mjs carries the canonical marimbaba melody + whistlegraph MOTIFS as reusable data. 25 variations/*.mjs, each with strong melodic development (octave-scatter, diminution, inversion/retrograde, kotekan, canon, modal refraction, theme-and-variations, liquidation, additive, Shepard spiral...). Build artifacts (out/) gitignored.