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/index.js

@@ -0,0 +1,45 @@
+import crypto from 'crypto'
+import { urlAlphabet } from './url-alphabet/index.js'
+const POOL_SIZE_MULTIPLIER = 128
+let pool, poolOffset
+let fillPool = bytes => {
+  if (!pool || pool.length < bytes) {
+    pool = Buffer.allocUnsafe(bytes * POOL_SIZE_MULTIPLIER)
+    crypto.randomFillSync(pool)
+    poolOffset = 0
+  } else if (poolOffset + bytes > pool.length) {
+    crypto.randomFillSync(pool)
+    poolOffset = 0
+  }
+  poolOffset += bytes
+}
+let random = bytes => {
+  fillPool((bytes |= 0))
+  return pool.subarray(poolOffset - bytes, poolOffset)
+}
+let customRandom = (alphabet, defaultSize, getRandom) => {
+  let mask = (2 << (31 - Math.clz32((alphabet.length - 1) | 1))) - 1
+  let step = Math.ceil((1.6 * mask * defaultSize) / alphabet.length)
+  return (size = defaultSize) => {
+    let id = ''
+    while (true) {
+      let bytes = getRandom(step)
+      let i = step
+      while (i--) {
+        id += alphabet[bytes[i] & mask] || ''
+        if (id.length === size) return id
+      }
+    }
+  }
+}
+let customAlphabet = (alphabet, size = 21) =>
+  customRandom(alphabet, size, random)
+let nanoid = (size = 21) => {
+  fillPool((size |= 0))
+  let id = ''
+  for (let i = poolOffset - size; i < poolOffset; i++) {
+    id += urlAlphabet[pool[i] & 63]
+  }
+  return id
+}
+export { nanoid, customAlphabet, customRandom, urlAlphabet, random }