Update engage-native docs for Supabase migration

repositories/d-sports-engage-native.mdx

@@ -1,12 +1,12 @@
 ---
 title: "d-sports-engage-native"
-description: "Native iOS and Android app for D-Sports Engage. Expo 54, React Native, Clerk, RevenueCat, Thirdweb."
+description: "Native iOS and Android app for D-Sports Engage. Expo 54, React Native, Clerk, RevenueCat, Thirdweb, Supabase."
 icon: "smartphone"
 ---
 
 ## Overview
 
 **d-sports-engage-native** (package name: `engage-native`) is the native mobile app for D-Sports. It mirrors the core PWA experience on iOS and Android: wallet, shop, leaderboard, locker room, and profile.
 
 - **Run:** `bunx expo start` or `bun run start` — then press `a` for Android or `i` for iOS, or scan the QR code with Expo Go.
 
@@ -17,18 +17,19 @@
 | Framework  | Expo 54, React Native 0.81, React 19 |
 | Auth       | Clerk (Expo)              |
 | Payments   | RevenueCat (react-native-purchases) |
 | Web3       | Thirdweb                  |
+| Backend    | Supabase (client-side JS) |
 | State      | Zustand                   |
 | Storage    | MMKV                      |
 | UI         | Lucide React Native       |
 | Navigation | Expo Router               |
 | Package    | Bun                       |
 
 ## Features
 
 - **Wallet** — Tokens, holdings, pack opening, crypto checkout (via PWA backend)
 - **Shop** — Collectibles, cart, coin bundles, checkout
 - **Leaderboard** — Rankings and filters
 - **Locker room** — Social feed and engagement
 - **Profile** — User profile and settings
 - **Theme** — Dark/light mode (default dark)
@@ -36,12 +37,31 @@
 ## Getting started
 
 1. Clone the repository and run `bun install`.
-2. Configure environment (Clerk, RevenueCat, Thirdweb, API base URL) per repo README.
+2. Configure environment variables (see [environment variables](#environment-variables) below).
 3. Run `bunx expo start`.
 4. For development builds: `bun run build:dev` (EAS) or run with Expo dev client.
 
 The app targets both native and web (responsive) and uses the same backend (d-sports-api) as the PWA for API and checkout flows.
 
+## Environment variables
+
+All runtime-accessible variables use the `EXPO_PUBLIC_` prefix. Set these in your `.env` file:
+
+| Variable | Description |
+| -------- | ----------- |
+| `EXPO_PUBLIC_CLERK_PUBLISHABLE_KEY` | Clerk authentication publishable key |
+| `EXPO_PUBLIC_API_URL` | Base URL for the d-sports-api backend |
+| `EXPO_PUBLIC_TW_CLIENT_ID` | Thirdweb client ID for Web3 features |
+| `EXPO_PUBLIC_REVENUECAT_API_KEY` | RevenueCat API key for in-app purchases |
+| `EXPO_PUBLIC_REVENUECAT_APPSTORE_ID` | RevenueCat App Store identifier |
+| `EXPO_PUBLIC_REVENUECAT_ENTITLEMENT` | RevenueCat entitlement name (e.g., `premium`) |
+| `EXPO_PUBLIC_SUPABASE_URL` | Supabase project URL |
+| `EXPO_PUBLIC_SUPABASE_KEY` | Supabase publishable (anon) key |
+
+<Note>
+  The Supabase client is used for client-side features only — it does not connect directly to the database. The Supabase client is initialized in `lib/supabase.ts`.
+</Note>
+
 <Card title="Ecosystem overview" icon="map" href="/repositories/ecosystem-overview">
   See how the native app fits with the PWA, site, and Mic'd Up.
 </Card>