System layers
Layer 1 · API
abhackus-rest-api (Rust + Axum + SQLx) exposes auth, users, accounting, reporting and support with role-based rules and traceability.
Layer 2 · Data
PostgreSQL 14+ as source of truth, using DATABASE_URL=postgres://user:password@host:5432/abhackus and versioned migrations in abhackus-dborm/migrations.
Layer 3 · Interfaces
Web (Leptos + Tailwind) for daily operations and TUI (Ratatui) for terminal administration.
Layer 4 · Operations
ODS import, admin validation for sensitive payments, periodic reconciliation and exportable reports.