Move native level setups into level files

- Delete NativeLevelFixtures.kt and make native repository setup an optional property of each Level.
- Move every existing native setup into its corresponding level file so setup, validation, and tests stay together.
- Add the missing Blame native setup with config.rb history and a Spider Man password commit.
- Add a native runtime regression that verifies `git blame config.rb` identifies Spider Man on the password line.
- Verify the full JVM test suite using the compiled host Git runtime.

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

@@ -232,6 +232,27 @@ class GitSandboxEngineTest {
         }
     }
 
+    @Test
+    fun nativeBlameLevelShowsPasswordAuthor() {
+        val git = testGitBinary()
+        assumeTrue(git.exists() && git.canExecute())
+        val root = Files.createTempDirectory("githug-blame-level").toFile()
+        try {
+            val runtime = GitRepositoryRuntime(root, git)
+            val level = blameLevel()
+            val repo = runtime.prepareLevel(level)
+
+            assertTrue(repo.files.single { it.name == "config.rb" }.content.contains("password"))
+
+            val (_, blameOutput) = runtime.execute(level, repo, "git blame config.rb")
+
+            assertTrue(blameOutput.any { it.contains("Spider Man") && it.contains("password") })
+            assertTrue(level.validator(repo, "Spider Man"))
+        } finally {
+            root.deleteRecursively()
+        }
+    }
+
     @Test
     fun cdDotDotShortcutMovesToParentDirectory() {
         val repo = RepoState(initialized = true, currentDir = "src/main")