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/nanoid/README.md

@@ -0,0 +1,39 @@
+# Nano ID
+
+<img src="https://ai.github.io/nanoid/logo.svg" align="right"
+     alt="Nano ID logo by Anton Lovchikov" width="180" height="94">
+
+**English** | [Русский](./README.ru.md) | [简体中文](./README.zh-CN.md) | [Bahasa Indonesia](./README.id-ID.md)
+
+A tiny, secure, URL-friendly, unique string ID generator for JavaScript.
+
+> “An amazing level of senseless perfectionism,
+> which is simply impossible not to respect.”
+
+* **Small.** 130 bytes (minified and gzipped). No dependencies.
+  [Size Limit] controls the size.
+* **Fast.** It is 2 times faster than UUID.
+* **Safe.** It uses hardware random generator. Can be used in clusters.
+* **Short IDs.** It uses a larger alphabet than UUID (`A-Za-z0-9_-`).
+  So ID size was reduced from 36 to 21 symbols.
+* **Portable.** Nano ID was ported
+  to [20 programming languages](#other-programming-languages).
+
+```js
+import { nanoid } from 'nanoid'
+model.id = nanoid() //=> "V1StGXR8_Z5jdHi6B-myT"
+```
+
+Supports modern browsers, IE [with Babel], Node.js and React Native.
+
+[online tool]: https://gitpod.io/#https://github.com/ai/nanoid/
+[with Babel]:  https://developer.epages.com/blog/coding/how-to-transpile-node-modules-with-babel-and-webpack-in-a-monorepo/
+[Size Limit]:  https://github.com/ai/size-limit
+
+<a href="https://evilmartians.com/?utm_source=nanoid">
+  <img src="https://evilmartians.com/badges/sponsored-by-evil-martians.svg"
+       alt="Sponsored by Evil Martians" width="236" height="54">
+</a>
+
+## Docs
+Read full docs **[here](https://github.com/ai/nanoid#readme)**.