fix(dual-screen): listen for game telemetry on 127.0.0.1, not ::1

Android's InetAddress.getLoopbackAddress() always returns the IPv6
loopback (libcore InetAddress.java, "Android-changed"), so the listeners
were bound to [::1] and never saw the games' IPv4 packets to 127.0.0.1.
A listener bound to 127.0.0.1:20777 on the same Duo received DiRT
Showdown's packets.

app/src/main/java/com/droiddeck/launcher/session/GameTelemetry.kt

@@ -33,6 +33,9 @@ object GameTelemetry {
     const val OUTGAUGE_PORT = 4444
     val PORTS = listOf(CODEMASTERS_PORT, FORZA_PORT, OUTGAUGE_PORT)
 
+    // Games send to 127.0.0.1; on Android InetAddress.getLoopbackAddress() is ::1, which IPv4 packets never reach.
+    val LISTEN_ADDRESS: java.net.InetAddress = java.net.InetAddress.getByAddress(byteArrayOf(127, 0, 0, 1))
+
     fun parse(port: Int, data: ByteArray, length: Int): Telemetry? = runCatching {
         val buf = ByteBuffer.wrap(data, 0, length).order(ByteOrder.LITTLE_ENDIAN)
         when (port) {

app/src/main/java/com/droiddeck/launcher/ui/BottomTelemetryPage.kt

@@ -49,7 +49,6 @@ import java.io.File
 import java.net.DatagramPacket
 import java.net.DatagramSocket
 import java.net.HttpURLConnection
-import java.net.InetAddress
 import java.net.InetSocketAddress
 import java.net.SocketTimeoutException
 import java.net.URL
@@ -92,7 +91,7 @@ fun BottomTelemetryPage(fps: () -> Float?) {
                 DatagramSocket(null).apply {
                     reuseAddress = true
                     soTimeout = 500
-                    bind(InetSocketAddress(InetAddress.getLoopbackAddress(), port))
+                    bind(InetSocketAddress(GameTelemetry.LISTEN_ADDRESS, port))
                 }
             }.getOrNull()
             if (socket == null) {

app/src/test/java/com/droiddeck/launcher/session/GameTelemetryTest.kt

@@ -2,6 +2,7 @@ package com.droiddeck.launcher.session
 
 import org.junit.Assert.assertEquals
 import org.junit.Assert.assertNull
+import org.junit.Assert.assertTrue
 import org.junit.Test
 import org.junit.runner.RunWith
 import org.robolectric.RobolectricTestRunner
@@ -112,6 +113,11 @@ class GameTelemetryTest {
         assertEquals(4000f, t.rpm!!, 0.01f)
     }
 
+    @Test fun listensOnIpv4Loopback() {
+        assertTrue(GameTelemetry.LISTEN_ADDRESS is java.net.Inet4Address)
+        assertEquals("127.0.0.1", GameTelemetry.LISTEN_ADDRESS.hostAddress)
+    }
+
     @Test fun shortPacketsAreIgnored() {
         assertNull(GameTelemetry.parse(GameTelemetry.CODEMASTERS_PORT, ByteArray(148), 148))
         assertNull(GameTelemetry.parse(GameTelemetry.OUTGAUGE_PORT, ByteArray(40), 40))