Phase 11 — API Hardening & Documentation

[aaqib-hafeez-khan-in]

Parent epic: #3

Objective

Harden the public API and developer experience as LedgerFlow grows into a multi-component financial simulation.

Scope

• Expand REST APIs for transactions, ledger, reconciliation, settlement, and operational diagnostics.
• Standardize error responses.
• Document APIs with OpenAPI/Swagger.
• Add realistic request/response examples.
• Keep local development setup simple and reproducible.
• Document architecture boundaries and operational workflows.

Acceptance criteria

• Public endpoints have consistent contracts and errors.
• OpenAPI documentation reflects the implemented APIs.
• Examples cover representative success and failure cases.
• A new developer can run and exercise the system using documented steps.

Out of scope

• Production deployment guarantees
• Real external payment integrations

Delivery

Implement as a focused PR linked back to #3.