True curved response, provably no overshoot outside [0,1]; collinear knots reproduce the exact linear ramp so linear()'s null-response stays bit-exact. Eval-only; v7 wire-format untouched. Adds spline tests.
Default flat y=1 (R10-F1 Option A) replaces the linear velocity/127 at note-on — a deliberate, non-back-compat behavior change; v1-v6 blobs lift to the flat default.
daniel