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/vary/README.md

@@ -0,0 +1,101 @@
+# vary
+
+[![NPM Version][npm-image]][npm-url]
+[![NPM Downloads][downloads-image]][downloads-url]
+[![Node.js Version][node-version-image]][node-version-url]
+[![Build Status][travis-image]][travis-url]
+[![Test Coverage][coveralls-image]][coveralls-url]
+
+Manipulate the HTTP Vary header
+
+## Installation
+
+This is a [Node.js](https://nodejs.org/en/) module available through the
+[npm registry](https://www.npmjs.com/). Installation is done using the
+[`npm install` command](https://docs.npmjs.com/getting-started/installing-npm-packages-locally): 
+
+```sh
+$ npm install vary
+```
+
+## API
+
+<!-- eslint-disable no-unused-vars -->
+
+```js
+var vary = require('vary')
+```
+
+### vary(res, field)
+
+Adds the given header `field` to the `Vary` response header of `res`.
+This can be a string of a single field, a string of a valid `Vary`
+header, or an array of multiple fields.
+
+This will append the header if not already listed, otherwise leaves
+it listed in the current location.
+
+<!-- eslint-disable no-undef -->
+
+```js
+// Append "Origin" to the Vary header of the response
+vary(res, 'Origin')
+```
+
+### vary.append(header, field)
+
+Adds the given header `field` to the `Vary` response header string `header`.
+This can be a string of a single field, a string of a valid `Vary` header,
+or an array of multiple fields.
+
+This will append the header if not already listed, otherwise leaves
+it listed in the current location. The new header string is returned.
+
+<!-- eslint-disable no-undef -->
+
+```js
+// Get header string appending "Origin" to "Accept, User-Agent"
+vary.append('Accept, User-Agent', 'Origin')
+```
+
+## Examples
+
+### Updating the Vary header when content is based on it
+
+```js
+var http = require('http')
+var vary = require('vary')
+
+http.createServer(function onRequest (req, res) {
+  // about to user-agent sniff
+  vary(res, 'User-Agent')
+
+  var ua = req.headers['user-agent'] || ''
+  var isMobile = /mobi|android|touch|mini/i.test(ua)
+
+  // serve site, depending on isMobile
+  res.setHeader('Content-Type', 'text/html')
+  res.end('You are (probably) ' + (isMobile ? '' : 'not ') + 'a mobile user')
+})
+```
+
+## Testing
+
+```sh
+$ npm test
+```
+
+## License
+
+[MIT](LICENSE)
+
+[npm-image]: https://img.shields.io/npm/v/vary.svg
+[npm-url]: https://npmjs.org/package/vary
+[node-version-image]: https://img.shields.io/node/v/vary.svg
+[node-version-url]: https://nodejs.org/en/download
+[travis-image]: https://img.shields.io/travis/jshttp/vary/master.svg
+[travis-url]: https://travis-ci.org/jshttp/vary
+[coveralls-image]: https://img.shields.io/coveralls/jshttp/vary/master.svg
+[coveralls-url]: https://coveralls.io/r/jshttp/vary
+[downloads-image]: https://img.shields.io/npm/dm/vary.svg
+[downloads-url]: https://npmjs.org/package/vary