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-dom/index.js

@@ -0,0 +1,38 @@
+'use strict';
+
+function checkDCE() {
+  /* global __REACT_DEVTOOLS_GLOBAL_HOOK__ */
+  if (
+    typeof __REACT_DEVTOOLS_GLOBAL_HOOK__ === 'undefined' ||
+    typeof __REACT_DEVTOOLS_GLOBAL_HOOK__.checkDCE !== 'function'
+  ) {
+    return;
+  }
+  if (process.env.NODE_ENV !== 'production') {
+    // This branch is unreachable because this function is only called
+    // in production, but the condition is true only in development.
+    // Therefore if the branch is still here, dead code elimination wasn't
+    // properly applied.
+    // Don't change the message. React DevTools relies on it. Also make sure
+    // this message doesn't occur elsewhere in this function, or it will cause
+    // a false positive.
+    throw new Error('^_^');
+  }
+  try {
+    // Verify that the code above has been dead code eliminated (DCE'd).
+    __REACT_DEVTOOLS_GLOBAL_HOOK__.checkDCE(checkDCE);
+  } catch (err) {
+    // DevTools shouldn't crash React, no matter what.
+    // We should still report in case we break this code.
+    console.error(err);
+  }
+}
+
+if (process.env.NODE_ENV === 'production') {
+  // DCE check should happen before ReactDOM bundle executes so that
+  // DevTools can report bad minification during injection.
+  checkDCE();
+  module.exports = require('./cjs/react-dom.production.min.js');
+} else {
+  module.exports = require('./cjs/react-dom.development.js');
+}