Cancels the curve-node drag whenever the popup closes so Esc mid-drag can't alias the amp curve; generalizes CurveTarget routing to one switch; fixes stale/overstated comments; clamps a pre-v12 depth fold; adds deck-inertness and filter-fold test coverage.
Cutoff-only re-solve (15.5 vs 56.9 ns/frame) makes the unquantized sweep
affordable, replacing the 2048-step mod quantizer. Live-compute parameters
remain blocked on a shell-architecture ruling.
daniel