Add Milestones 1 & 2: full-stack POS foundation with admin UI

- Node/Express/TypeScript API under /api/v1 with JWT auth (login, refresh, logout, /me)
- Prisma schema: vendors, users, roles, products, categories, taxes, transactions
- SQLite for local dev; Postgres via docker-compose for production
- Full CRUD routes for vendors, users, categories, taxes, products with Zod validation and RBAC
- Paginated list endpoints scoped per vendor; refresh token rotation
- React/TypeScript admin SPA (Vite): login, protected routing, sidebar layout
- Pages: Dashboard, Catalog (tabbed Products/Categories/Taxes), Users, Vendor Settings
- Shared UI: Table, Modal, FormField, Btn, PageHeader components
- Multi-stage Dockerfile; docker-compose with Postgres healthcheck
- Seed script with demo vendor and owner account
- INSTRUCTIONS.md, ROADMAP.md, .claude/launch.json for dev server config

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ROADMAP.md

@@ -0,0 +1,45 @@
+# ROADMAP.md
+
+## Milestone 1 — Foundation ✅
+- [x] Node/TypeScript API skeleton with Express
+- [x] Health check endpoint (`GET /api/v1/health`)
+- [x] JWT auth: login, refresh, logout, /me
+- [x] Prisma schema: vendors, users, roles, products, categories, taxes, transactions
+- [x] SQLite for local dev; Postgres for production
+- [x] React admin SPA (Vite + TypeScript)
+- [x] Login page + protected routing
+- [x] Dashboard shell with auth context
+- [x] Multi-stage Dockerfile; docker-compose with Postgres
+- [x] Seed script with demo data
+
+---
+
+## Milestone 2 — Core Data & Admin ✅
+- [x] Full CRUD: vendors, users, categories, products, taxes
+- [x] RBAC enforcement on all routes (owner / manager / cashier)
+- [x] Vendor settings page in admin UI
+- [x] User management UI (add, edit, delete, assign role)
+- [x] Catalog management UI (products, categories, taxes — tabbed)
+- [x] Input validation with Zod on all endpoints
+- [x] Pagination on list endpoints
+
+---
+
+## Milestone 3 — Android & Offline Sync
+- [ ] `GET /api/v1/catalog/sync?since=` for delta syncs
+- [ ] `POST /api/v1/transactions/batch` with idempotency keys
+- [ ] Android Kotlin app: MVVM, Room, offline-first flows
+- [ ] Background sync worker (Android)
+- [ ] Conflict resolution strategy: server-authoritative for payments
+- [ ] Admin reporting: Android-originated transactions appear in reports
+
+---
+
+## Milestone 4 — Payments & Hardening
+- [ ] Payment abstraction layer (cash + card stub; provider-agnostic)
+- [ ] Shift/daily summary endpoint and UI
+- [ ] Receipt generation (print / email hooks)
+- [ ] Advanced reporting: sales by product, tax summaries
+- [ ] Telemetry and structured logging
+- [ ] Production Docker hardening (non-root user, health checks, secrets)
+- [ ] CI/CD pipeline skeleton