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/src/app.ts

@@ -0,0 +1,50 @@
+import express from "express";
+import cors from "cors";
+import path from "path";
+import { fileURLToPath } from "url";
+import healthRouter from "./routes/health.js";
+import authRouter from "./routes/auth.js";
+import vendorsRouter from "./routes/vendors.js";
+import usersRouter from "./routes/users.js";
+import categoriesRouter from "./routes/categories.js";
+import taxesRouter from "./routes/taxes.js";
+import productsRouter from "./routes/products.js";
+import { errorHandler } from "./middleware/errorHandler.js";
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
+export function createApp() {
+  const app = express();
+
+  app.use(
+    cors({
+      origin: process.env.CORS_ORIGIN ?? "*",
+      credentials: true,
+    })
+  );
+  app.use(express.json());
+  app.use(express.urlencoded({ extended: true }));
+
+  // API routes
+  app.use("/api/v1", healthRouter);
+  app.use("/api/v1/auth", authRouter);
+  app.use("/api/v1/vendors", vendorsRouter);
+  app.use("/api/v1/users", usersRouter);
+  app.use("/api/v1/categories", categoriesRouter);
+  app.use("/api/v1/taxes", taxesRouter);
+  app.use("/api/v1/products", productsRouter);
+
+  // Serve React admin UI static assets in production
+  if (process.env.NODE_ENV === "production") {
+    const clientDist = path.join(__dirname, "../../client/dist");
+    app.use(express.static(clientDist));
+    app.get(/^(?!\/api).*/, (_req, res) => {
+      res.sendFile(path.join(clientDist, "index.html"));
+    });
+  }
+
+  app.use(errorHandler);
+
+  return app;
+}