Align tests with runtime sandbox and polish terminal help

- Run level solution scenarios through GitRepositoryRuntime with a real filesystem sandbox and git binary so evidence logs match app behavior.
- Materialize synthetic remotes as local bare repositories and configure upstream tracking for pull/push levels.
- Route mobile-hostile Git interactions through shared sandbox semantics for clone, patch add, interactive rebase, squash merge, submodule, stash, revert, and related flows.
- Relax affected level validators to inspect observable runtime state instead of fallback-only staged/index details.
- Show .git in ls output for native and fallback helper commands.
- Make tab completion resolve filenames and directories relative to the current working directory.
- Integrate help controls into the callout overlay and reposition the prompt callout above the terminal prompt.
- Add regression coverage for .git listing and subfolder completion.

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

@@ -122,6 +122,31 @@ class GitSandboxEngineTest {
         assertTrue(".gitignore" in output)
     }
 
+    @Test
+    fun lsShowsGitDirectoryEntry() {
+        val repo = RepoState(initialized = true)
+
+        val (_, output) = GitSandboxEngine.execute(repo, "ls")
+
+        assertTrue(".git" in output)
+    }
+
+    @Test
+    fun fileCompletionUsesCurrentDirectory() {
+        val repo = RepoState(
+            initialized = true,
+            currentDir = "src",
+            files = listOf(
+                GitFile("README"),
+                GitFile("src/main.kt"),
+                GitFile("src/model/User.kt"),
+            ),
+        )
+
+        assertEquals(listOf("main.kt", "model/User.kt"), fileCompletionCandidates(repo).sorted())
+        assertEquals(listOf("model/"), directoryCompletionCandidates(repo))
+    }
+
     @Test
     fun cdDotDotShortcutMovesToParentDirectory() {
         val repo = RepoState(initialized = true, currentDir = "src/main")

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

@@ -31,22 +31,30 @@ class LevelSolutionsTest {
     @Test
     fun knownSolutionsCompleteEveryLevel() {
         val evidence = StringBuilder()
+        val gitBinary = systemGitBinary()
+        val runtimeRoot = testSandboxRoot().apply {
+            deleteRecursively()
+            mkdirs()
+        }
         evidence.appendLine("GitHug Android level solution evidence")
-        evidence.appendLine("Engine: GitSandboxEngine fallback")
-        evidence.appendLine("Scope: validates fallback command handling and level validators; native runtime setup is covered by app runtime tests/builds.")
+        evidence.appendLine("Engine: GitRepositoryRuntime filesystem sandbox")
+        evidence.appendLine("Git binary: ${gitBinary.absolutePath}")
+        evidence.appendLine("Sandbox root: ${runtimeRoot.absolutePath}")
+        evidence.appendLine("Scope: executes embedded solution scenarios through the same runtime and per-level sandbox path used by the app.")
         evidence.appendLine("Levels: ${allGithugLevels().size}")
         evidence.appendLine()
 
         val failures = allGithugLevels().flatMap { level ->
+            val runtime = GitRepositoryRuntime(runtimeRoot, gitBinary)
             evidence.appendLine("================================================================================")
             evidence.appendLine("Level: ${level.id}")
             evidence.appendLine("Title: ${level.title}")
             evidence.appendLine("Initial repo:")
-            evidence.append(level.setup().describeForEvidence().prependIndent("  "))
+            evidence.append(runtime.prepareLevel(level).describeForEvidence().prependIndent("  "))
             evidence.appendLine()
 
             level.testCases.mapNotNull { testCase ->
-                var repo = level.setup()
+                var repo = runtime.prepareLevel(level)
                 var solved = false
 
                 evidence.appendLine("Scenario: ${testCase.name}")
@@ -57,7 +65,7 @@ class LevelSolutionsTest {
                 evidence.appendLine()
 
                 testCase.commands.forEachIndexed { index, command ->
-                    val (nextRepo, output) = GitSandboxEngine.execute(repo, command)
+                    val (nextRepo, output) = runtime.execute(level, repo, command)
                     repo = nextRepo
                     solved = level.validator(repo, command)
 
@@ -102,6 +110,32 @@ class LevelSolutionsTest {
             File(reportDir, "level-solutions.log").writeText(content)
         }
 
+        fun testSandboxRoot(): File {
+            val repoRoot = File(System.getProperty("user.dir") ?: ".")
+            val appDir = if (File(repoRoot, "app/build.gradle.kts").exists()) {
+                File(repoRoot, "app")
+            } else {
+                repoRoot
+            }
+            return File(appDir, "build/test-sandboxes/level-solutions")
+        }
+
+        fun systemGitBinary(): File {
+            val candidates = listOf(
+                File("/usr/bin/git"),
+                File("/usr/local/bin/git"),
+            )
+            candidates.firstOrNull { it.exists() && it.canExecute() }?.let { return it }
+
+            val process = ProcessBuilder("sh", "-c", "command -v git")
+                .redirectErrorStream(true)
+                .start()
+            val output = process.inputStream.bufferedReader().readText().trim()
+            val exitCode = process.waitFor()
+            assertTrue("A real git executable is required for level solution tests.", exitCode == 0 && output.isNotBlank())
+            return File(output)
+        }
+
         fun RepoState.describeForEvidence(): String = buildString {
             appendLine("initialized=$initialized")
             appendLine("headBranch=$headBranch")