Add new module: Disclosure.fs (FCA CONC, EU SECCI, US TILA)

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Adds a new Disclosure.fs module that computes the key regulatory metrics required for consumer credit documentation across UK, EU and US regimes.

Changes Made

src/Disclosure.fs (new)

Three public disclosure functions, each accepting Amortisation.Schedule as their primary input so all figures remain consistent with the amortisation model:

Function	Regime	Key figures
ukConc aprPrecision schedule	UK FCA MCOB / CONC App 1.2	APR, Total Cost of Credit, Total Amount Payable, Representative APR
euSecci aprPrecision schedule	EU Directive 2008/48/EC (SECCI)	APR, TCC, TAP
euSecciRepaymentSchedule schedule	EU SECCI repayment schedule	EuSecciRepaymentEntry array — date and amount per payment
usTila aprPrecision schedule	US TILA / Regulation Z (12 CFR Part 1026 Appendix J)	Finance Charge, Amount Financed (principal minus prepaid day-0 fees), APR

APR for each regime is computed using the existing Apr.calculate infrastructure with the appropriate method (UnitedKingdom, EuropeanUnion, UsActuarial). TCC is derived directly from the schedule's InterestPortion + FeePortion + ChargesPortion per-item totals.

tests/DisclosureTests.fs (new)

22 unit tests across UkConcTests, EuSecciTests, and UsTilaTests covering:

• TAP = principal + TCC invariant
• TCC equals BasicSchedule.Stats.InterestTotal for fee-free loans
• APR positivity and consistency with InitialApr from BasicSchedule
• Repayment schedule length, positive amounts, ascending dates, and total matching TAP
• TILA amount-financed equals principal when there are no prepaid fees

Testing

• ✅ Build succeeds with 0 warnings/errors
• ✅ All 22 new disclosure tests pass
• ✅ No regressions introduced (219 pre-existing failures in HTML-generation code remain unchanged)

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Done — commit 43f64e1 adds the full Disclosure.fs module (and DisclosureTests.fs). Here's a summary of what was implemented:

src/Disclosure.fs — three public functions, each accepting Amortisation.Schedule as primary input:

Function	Regime	Returns
ukConc aprPrecision schedule	UK FCA CONC App 1.2	UkConc — APR, TCC, Total Amount Payable, Representative APR
euSecci aprPrecision schedule	EU Directive 2008/48/EC	EuSecci — APR, TCC, Total Amount Payable
euSecciRepaymentSchedule schedule	EU SECCI sheet	EuSecciRepaymentEntry array — (date, amount) pairs
usTila aprPrecision schedule	US TILA / Reg Z	UsTila — Finance Charge, Amount Financed (principal minus day-0 prepaid fees), APR

APR for each regime is computed using the existing Apr.calculate infrastructure with the appropriate method (UnitedKingdom, EuropeanUnion, UsActuarial). TCC is derived directly from the schedule's InterestPortion + FeePortion + ChargesPortion totals.

tests/DisclosureTests.fs — 22 passing unit tests covering all three regimes, including invariant checks (TAP = principal + TCC), consistency with BasicSchedule.Stats, and APR range assertions.