fix: correct stale 'electrum' references in build scripts and Java classes

- apprun.sh: exec electrum-purple (was: electrum) — AppImage would fail to launch
- electrum-purple.nsi: shortcuts point to electrum-purple-VERSION.exe (was: electrum-VERSION.exe)
- SimpleScannerActivity.java: import org.electrumpurple.electrum_purple.res.R
- BiometricActivity.java: import org.electrumpurple.electrum_purple.res.R + title Electrum Purple
- run_electrum: is_local check looks for electrum-purple.desktop

electrum/gui/qml/java_classes/org/electrum/biometry/BiometricActivity.java

@@ -22,7 +22,7 @@ import javax.crypto.KeyGenerator;
 import javax.crypto.SecretKey;
 import javax.crypto.spec.IvParameterSpec;
 
-import org.electrum.electrum.res.R;
+import org.electrumpurple.electrum_purple.res.R;
 
 public class BiometricActivity extends Activity {
     private static final String TAG = "BiometricActivity";
@@ -54,7 +54,7 @@ public class BiometricActivity extends Activity {
 
         Executor executor = getMainExecutor();
         BiometricPrompt biometricPrompt = new BiometricPrompt.Builder(this)
-                .setTitle("Electrum Wallet")
+                .setTitle("Electrum Purple")
                 .setAllowedAuthenticators(BiometricManager.Authenticators.BIOMETRIC_STRONG | BiometricManager.Authenticators.DEVICE_CREDENTIAL)
                 .setSubtitle(authMessage)
                 .build();

electrum/gui/qml/java_classes/org/electrum/qr/SimpleScannerActivity.java

@@ -27,7 +27,7 @@ import de.markusfisch.android.zxingcpp.ZxingCpp.Result;
 import de.markusfisch.android.zxingcpp.ZxingCpp.ContentType;
 
 
-import org.electrum.electrum.res.R; // package set in build.gradle
+import org.electrumpurple.electrum_purple.res.R; // package set in build.gradle
 
 public class SimpleScannerActivity extends Activity {
     private static final int MY_PERMISSIONS_CAMERA = 1002;