refactor: rename package to lostmyphone.app

Move off the reserved com.example placeholder namespace to the app's own
package identifier.

README.md

@@ -3,7 +3,7 @@
 An Android app that listens for SMS commands to trigger a loud ring — overriding
 "Do Not Disturb" (DND) — so you can find your phone.
 
-- **Package:** `com.example.lostmyphone`
+- **Package:** `lostmyphone.app`
 - **No Google Play Services.** Pure Android SDK.
 - **Languages:** Kotlin, Material Components (AndroidX).
 
@@ -132,7 +132,7 @@ settings instead.
 ## Architecture
 
 ```
-app/src/main/java/com/example/lostmyphone/
+app/src/main/java/lostmyphone/app/
 ├── MainActivity.kt   # UI: status, permission requests, DND-access launcher, manual test
 ├── SmsReceiver.kt    # BroadcastReceiver: parses SMS -> detects RING_NOW / PLAY_SONG
 └── RingService.kt    # ForegroundService: DND gate, volume override, focus + playback, 30s timer