docs(readme): document pnpm + Vite workflow

Replaces the Vue CLI / npm commands with pnpm dev/build/typecheck/lint
and lists the VITE_* env vars the new code expects.

README.md

@@ -1,26 +1,40 @@
 # Vaquant
 
-## Project setup
-```
-npm install
+Manage group budgets — Vue 3 + Vite + Pinia + Tailwind/DaisyUI + CouchDB (PouchDB).
+
+## Requirements
+
+- Node 22+ (see `.node-version`)
+- pnpm 10+ (`corepack enable && corepack prepare pnpm@latest --activate`)
+
+## Setup
+
+```sh
+pnpm install
 ```
 
-### Compiles and hot-reloads for development
-```
-npm run serve
+## Develop
+
+```sh
+pnpm dev          # Vite dev server on http://localhost:8080
+pnpm typecheck    # vue-tsc --noEmit
+pnpm lint         # ESLint
+pnpm test         # Vitest
 ```
 
-### Compiles and minifies for production
-```
-npm run build
+## Build
+
+```sh
+pnpm build        # Type-check, then build to dist/
+pnpm preview      # Serve the production build locally
 ```
 
-### Lints and fixes files
-```
-npm run lint
-```
+## Environment
+
+Create `.env` (gitignored) with:
 
-### Run your unit tests
 ```
-npm run test:unit
+VITE_COUCHDB=https://your-couchdb-host
+VITE_MAPBOX_KEY=pk.your-mapbox-token
+VITE_MAP_KEY=your-bing-maps-key
 ```