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>

server/node_modules/safe-buffer/index.js

@@ -0,0 +1,65 @@
+/*! safe-buffer. MIT License. Feross Aboukhadijeh <https://feross.org/opensource> */
+/* eslint-disable node/no-deprecated-api */
+var buffer = require('buffer')
+var Buffer = buffer.Buffer
+
+// alternative to using Object.keys for old browsers
+function copyProps (src, dst) {
+  for (var key in src) {
+    dst[key] = src[key]
+  }
+}
+if (Buffer.from && Buffer.alloc && Buffer.allocUnsafe && Buffer.allocUnsafeSlow) {
+  module.exports = buffer
+} else {
+  // Copy properties from require('buffer')
+  copyProps(buffer, exports)
+  exports.Buffer = SafeBuffer
+}
+
+function SafeBuffer (arg, encodingOrOffset, length) {
+  return Buffer(arg, encodingOrOffset, length)
+}
+
+SafeBuffer.prototype = Object.create(Buffer.prototype)
+
+// Copy static methods from Buffer
+copyProps(Buffer, SafeBuffer)
+
+SafeBuffer.from = function (arg, encodingOrOffset, length) {
+  if (typeof arg === 'number') {
+    throw new TypeError('Argument must not be a number')
+  }
+  return Buffer(arg, encodingOrOffset, length)
+}
+
+SafeBuffer.alloc = function (size, fill, encoding) {
+  if (typeof size !== 'number') {
+    throw new TypeError('Argument must be a number')
+  }
+  var buf = Buffer(size)
+  if (fill !== undefined) {
+    if (typeof encoding === 'string') {
+      buf.fill(fill, encoding)
+    } else {
+      buf.fill(fill)
+    }
+  } else {
+    buf.fill(0)
+  }
+  return buf
+}
+
+SafeBuffer.allocUnsafe = function (size) {
+  if (typeof size !== 'number') {
+    throw new TypeError('Argument must be a number')
+  }
+  return Buffer(size)
+}
+
+SafeBuffer.allocUnsafeSlow = function (size) {
+  if (typeof size !== 'number') {
+    throw new TypeError('Argument must be a number')
+  }
+  return buffer.SlowBuffer(size)
+}