The post-CGA / ProblemFrame pivot comes to fruition: geometric dilation for
fraction_decrease is built from the bound scale role's GroundedScalar
(exact Fraction from kernel slash_fraction / pack numerics), not from a
local "decrease to N/M of" regex on evidence spans.
- Remove _build_fraction_decrease_payload_and_bind (legacy overfitting path)
- Add _fraction_decrease_scale_binding + _versor_binding_from_scale_value
- assess_fraction_decrease attaches VersorBindings when runnable
- assess_geometric_proposals uses frame scale only for fraction_decrease
- compose fallback prefers obligation-complete contracts with bindings
- Guard test: contracts source must not reintroduce the prose regex
Invariants: construction-boundary CGA only; versor_condition < 1e-6;
no new derivation-organ prose parser.
