Solos: the lead improvises over the changes

Task #23, never started: sec.solo/LICKS existed but the concept didn't. Now five idiomatic genres — bebop, jazz, blues, funk, bluegrass — get a real solo section where the lead improvises over the chord changes, not a pattern table.

• The improviser (csd-engine melodyEvents "solo"): per chord bar it builds a line from the chord tones (lead[]) with scale-step connectors and CHROMATIC APPROACH notes into the next target (the bop enclosure)…

• The solo section (genre-kernel buildSections): spliced before the final head (head -> SOLO -> head), the genre's own lead voice takes it, the comp ducks (soloDuck halves the pad bed so the line sits forward).

Verified: matrix 228/228 --no-cache (the dense solo section moves melody/motion features but no genre loses itself), verify.sh green (validate + engine + prove, incl.

▶ Play it: Crossroads Paperwork → Mercury Interrogation → Centrifugal Hymnal — the three genres this change names, as one path https://stellate.app/?genre=blues&seed=3870&path=1036.22151,694.13856,1618.5296&xdur=0.044

3433f35 https://github.com/aboard-io/stellate/commit/3433f35eb1eb244ff26e6902c4a7257d2bac4c57