# Proposal: fulfillment-invoices

## Why
After payment, merchants ship goods (发货单) and customers request invoices (发票). This phase closes the post-order loop of the MVP.

## What changes
- Schema: shipments (carrier, tracking, status, per-item qty), invoices (title, tax_no, kind, amount, status).
- Shipment lifecycle: created(pending) → shipped → delivered; order becomes fulfilling on first shipment, shipped when all items shipped, completed when all delivered (customer confirm allowed).
- Merchant APIs: create shipment for paid/fulfilling orders, mark shipped, list shipments/invoices, issue invoice.
- Customer APIs: my shipments, confirm delivery, request invoice per order, my invoices.

## Non-goals
- Carrier API integrations, e-invoice/PDF generation, partial invoice amounts.

## Capabilities
- `shipment`: 发货单 lifecycle.
- `invoice`: 发票 request/issue lifecycle.