Client Billing

Full billing module: contract-driven rate cards, outcome-based billing logic, invoice generation, and a margin dashboard per client. Supersedes the Wave 1.5 billable-hours ledger. Sub-spec 34A (Contract Lifecycle Management) handles MSAs, SOWs, amendments, SLA clauses, and renewals. Built so finance and account managers stop reconciling T&A actuals against client invoices in Excel.