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/lib/pagination.ts

@@ -0,0 +1,27 @@
+export interface PageParams {
+  page: number;
+  limit: number;
+  skip: number;
+}
+
+export function parsePage(query: Record<string, unknown>): PageParams {
+  const page = Math.max(1, parseInt(String(query.page ?? "1"), 10) || 1);
+  const limit = Math.min(100, Math.max(1, parseInt(String(query.limit ?? "20"), 10) || 20));
+  return { page, limit, skip: (page - 1) * limit };
+}
+
+export function paginatedResponse<T>(
+  data: T[],
+  total: number,
+  { page, limit }: PageParams
+) {
+  return {
+    data,
+    pagination: {
+      page,
+      limit,
+      total,
+      totalPages: Math.ceil(total / limit),
+    },
+  };
+}