getting-started: add PWA install note for the chat on phones

getting-started.md

@@ -62,6 +62,20 @@ Your usage draws from your monthly allowance; you can see it on the
 If the chat ever says your balance is out, that's the allowance, not an error —
 see "Your allowance" below.
 
+### Add the chat to your phone
+
+The chat works like an app on your phone — no app store needed. Open
+[chat.inference.coop](https://chat.inference.coop) in your phone's browser and
+log in, then:
+
+- **iPhone (Safari):** tap the **Share** button (the square with an arrow),
+  then **Add to Home Screen**.
+- **Android (Chrome):** tap the **⋮** menu, then **Add to Home Screen**
+  (or **Install app**).
+
+You'll get an icon on your home screen that opens the chat full-screen, like
+any other app. Your login stays active — just tap and chat.
+
 ## 3. Get involved in governance
 
 You don't just use the co-op; you help run it. Decisions about models, pricing,