Retrieve Gusto payroll journal data for general ledger posting

Steps

1. Authenticate with Gusto via OAuth 2.0; obtain access tokens for the employer account and note the company_id (UUID) for the target company.
2. GET https://api.gusto.com/v1/companies/{company_id}/payrolls to retrieve the list of payrolls; filter by processed:true and use start_date/end_date parameters to scope a date range.
3. For each payroll of interest, retrieve detailed breakdowns via GET https://api.gusto.com/v1/companies/{company_id}/payrolls/{payroll_id} with the include=benefits,deductions,taxes query parameter.
4. Parse the employee_compensations array for each payroll; each entry contains gross_pay, net_pay, employee and employer taxes (broken out by type), benefit deductions, and garnishments.
5. Aggregate these amounts by GL account category (gross wages, employer FICA, employee deductions, net pay liability) to build journal entry lines.
6. POST the resulting journal entry to your accounting system; debit expense accounts (wages, employer taxes) and credit liability accounts (wages payable, tax liabilities, benefit payables).