E2EE instructions in the example readme (#681)

Author: bcherry

example/README.md

@@ -12,3 +12,19 @@ flutter pub get
 # you can autofill URL and TOKEN for first run in debug mode.
 flutter run --dart-define=URL=wss://${LIVEKIT_SERVER_IP_OR_DOMAIN} --dart-define=TOKEN=${YOUR_TOKEN}
 ```
+
+## End-to-End Encryption (E2EE)
+
+The example app supports end-to-end encryption for audio and video tracks. To enable E2EE:
+
+1. Toggle the "E2EE" switch in the connect screen
+2. Enter a shared key that will be used for encryption
+3. All participants must use the same shared key to communicate
+
+For web support, you'll need to compile the E2EE web worker:
+
+```bash
+dart compile js web/e2ee.worker.dart -o example/web/e2ee.worker.dart.js -m
+```
+
+Note: All participants in the room must have E2EE enabled and use the same shared key to see and hear each other. If the keys don't match, participants won't be able to decode each other's audio and video.