Clarify grant rate decay formula in A.2.9.2.2.2.2.4

[pegaslint]

Problem

A.2.9.2.2.2.2.4 (Minimum Borrowing Threshold for Grant Eligibility) currently reads like the grant always covers the full (Base − TBill) difference (i.e., a constant full subsidy → effective rate always = TBill).

This conflicts with the ramping effective-rate formula in A.2.9.2.2.2.2.2 (Borrow Rate Mechanism).

Solution

Keep the effective-rate formula exactly as written in A.2.9.2.2.2.2.2, and define the grant so that it produces that effective rate:

Grant (reimbursement) rate:

grant_rate(T) = Base − effective_rate(T) = (Base − TBill) * (1 − T/24)

(clamped at ≥ 0 so no negative grants if Base ≤ TBill)

This makes explicit that the grant decays linearly from (Base − TBill) at T=0 down to 0 at T=24, exactly matching the effective-rate ramp.

Proposed Text Change

In A.2.9.2.2.2.2.4, replace:

"This grant will cover the difference between the borrowing Base Rate and the T-bill rate."

With:

"The monthly reimbursement grant decays linearly over the 24-month subsidy window so that the borrower's effective borrowing rate equals effective_rate(T) = TBill + (Base − TBill) * (T/24). Equivalently, the grant rate is grant_rate(T) = (Base − TBill) * (1 − T/24), clamped at ≥ 0."

Example (Sanity Check)

With Base = 8% and TBill = 4%:

Month (T)	Grant Rate	Effective Rate
T=0	4%	4%
T=12	2%	6%
T=24	0%	8%