App 2.19.3: update log on the Logs tab

Every update and install step, with the platform's own result, kept
across the restart an install causes, so a failed install on the car
can be read off the screen.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LhzAVaUyqcw5PkGjz4mWW6

app/src/test/java/com/evsuite/abrp/UpdateLogTest.java

@@ -0,0 +1,25 @@
+package com.evsuite.abrp;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+import org.junit.Test;
+
+/** The update log's line handling — pure JVM. */
+public class UpdateLogTest {
+
+    @Test
+    public void newestComesFirstAndTheOldestFallsOff() {
+        List<String> lines = UpdateLog.append(Arrays.asList("b", "a"), "c", 2);
+        assertEquals(Arrays.asList("c", "b"), lines);
+    }
+
+    @Test
+    public void aMultiLinePlatformMessageStaysOneLine() {
+        List<String> lines = UpdateLog.append(Collections.emptyList(), "failed:\nINSTALL_X\r", 10);
+        assertEquals(Collections.singletonList("failed: INSTALL_X "), lines);
+    }
+}