Add a moving bassline and a lead melody to the vaporwave sketch

instr 2 reworked from a static held root into a syncopated city-pop bass figure (root / octave / fifth movement), pluckier envelope so the line articulates; driven by a new BASS score macro per chord.

• instr 4 (new): lead melody — detuned sines + soft octave partial, gentle vibrato, reverb send. A wistful top line over both Royal Road passes via a MEL score macro.

• Score refactored to PAD/BASS/MEL macros so the harmony stays readable.

• Renders clean under csound 6.18, peak ~0.34, no clipping.

▶ Play it: Food Court Eternity — parked on the genre this change names https://stellate.app/?genre=vaporwave&seed=2822&path=1679.4393,1698.4426,1660.4426&xdur=13.122

cdb511a https://github.com/aboard-io/stellate/commit/cdb511ae3529d20c5a4bc6a10ec6bf7984d8c604