ASC 842 lease amortization schedule and monthly JE

Build an ASC 842 lease amortization schedule and monthly journal entries.

Inputs:
- Lease type (operating/finance): {lease_type}
- Commencement date: {commencement_date}
- Lease term (months) and options reasonably certain: {lease_term_months}
- Payment schedule: {payment_schedule}  # date, payment, fixed/variable
- Discount rate / IBR: {discount_rate}
- Initial direct costs & incentives: {initial_costs_incentives}

Output:
1) Amortization table by month: Payment, Interest, Principal, Ending liability.
2) ROU asset rollforward: Beginning, Additions, Amortization, Ending.
3) Monthly JE template for the period {period_to_book}.
4) Reasonableness checks (PV tie-out, straight-line expense if operating lease).

State assumptions clearly.