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/routes/health.ts

@@ -0,0 +1,25 @@
+import { Router, Request, Response } from "express";
+import { prisma } from "../lib/prisma.js";
+
+const router = Router();
+
+router.get("/health", async (_req: Request, res: Response) => {
+  let dbStatus = "ok";
+  try {
+    await prisma.$queryRaw`SELECT 1`;
+  } catch {
+    dbStatus = "error";
+  }
+
+  const status = dbStatus === "ok" ? "ok" : "degraded";
+  res.status(status === "ok" ? 200 : 503).json({
+    status,
+    timestamp: new Date().toISOString(),
+    version: process.env.npm_package_version ?? "0.1.0",
+    services: {
+      database: dbStatus,
+    },
+  });
+});
+
+export default router;