Constant RHO_TARGET_KNOTS

pub const RHO_TARGET_KNOTS: &[(i64, f64)];

Designed pressure profile — sparse knots, geometric interpolation. THE designer-editable difficulty curve: raise a knot to make that zone easier (player further ahead), lower it for pressure.

Units are zone-corrected: ρ̂ = P/(z(ch)·E(ch)) with z from ZONE_DIFFICULTY_KNOTS, so one value of ρ̂ means the SAME winrate in every zone — the measured 50%-crossing is ≈0.55 everywhere, and a flat stretch of the profile at ~0.65 plays as ~60% on-schedule winrate.

Shape: a glide from the pinned early anchor through the ch7-15 boss-gate zone down to a working plateau, then a declining late tail. There are no deliberate walls: pacing is carried by the resource schedule (E’s per-chapter step ≡ fundable growth per chapter at target cadence, so a blitz stalls within ~1-3 chapters and daily supply restores the cadence); the treadmill bounds are guarded by test_pacing_contract.

The values encode the ratified feel. Note the honest on-schedule winrate is NOT flat across zones (~65% around ch49 falling to ~20-25% at ch62-87); flattening it is a designer decision — it re-paces the late game — not a calibration fix. E = G/(ρ̂·z) is pinned by zone_correction_preserves_enemy_curve: never edit ρ̂ or z alone, only together with a re-derivation of the pair (and G).