Add exercise description onboarding bubble

Remove duplicate IME padding that caused keyboard gap
Add md alias for mkdir helper command
Add dir alias for ls helper command
Add cd.. shortcut for cd .. helper command

app/src/test/java/solutions/tretter/githugandroid/GitSandboxEngineTest.kt

@@ -1,5 +1,6 @@
 package solutions.tretter.githugandroid
 
+import org.junit.Assert.assertEquals
 import org.junit.Assert.assertFalse
 import org.junit.Assert.assertTrue
 import org.junit.Test
@@ -64,4 +65,36 @@ class GitSandboxEngineTest {
 
         assertTrue(commitHashAnswer("0000001")(repo, "abc1234fedcba9876543210fedcba9876543210"))
     }
+
+    @Test
+    fun mdIsAcceptedAsMkdirAlias() {
+        val repo = RepoState(initialized = true)
+
+        val (_, output) = GitSandboxEngine.execute(repo, "md src")
+
+        assertTrue(output.isEmpty())
+    }
+
+    @Test
+    fun dirIsAcceptedAsLsAlias() {
+        val repo = RepoState(
+            initialized = true,
+            files = listOf(GitFile("README"), GitFile("src/main.kt")),
+        )
+
+        val (_, output) = GitSandboxEngine.execute(repo, "dir")
+
+        assertTrue("README" in output)
+        assertTrue("src/main.kt" in output)
+    }
+
+    @Test
+    fun cdDotDotShortcutMovesToParentDirectory() {
+        val repo = RepoState(initialized = true, currentDir = "src/main")
+
+        val (updatedRepo, output) = GitSandboxEngine.execute(repo, "cd..")
+
+        assertTrue(output.isEmpty())
+        assertEquals("src", updatedRepo.currentDir)
+    }
 }