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>

client/node_modules/react-router/dist/lib/deprecations.d.ts

@@ -0,0 +1,4 @@
+import type { FutureConfig as RouterFutureConfig } from "@remix-run/router";
+import type { FutureConfig as RenderFutureConfig } from "./components";
+export declare function warnOnce(key: string, message: string): void;
+export declare function logV6DeprecationWarnings(renderFuture: Partial<RenderFutureConfig> | undefined, routerFuture?: Omit<RouterFutureConfig, "v7_prependBasename">): void;