Fix level setup, reword flow, and catalog scope

- create and enter the level's declared starting directory
- inspect Git state from the repository containing the active directory
- start the init level in /sandbox/git_hug and cover it with a runtime test
- apply edited reword subjects as commit messages in the in-app rebase editor
- cover rename_commit with a native interactive rebase regression test
- remove the upstream contribute call to action from the playable level catalog
- update level parity documentation

app/src/main/java/solutions/tretter/githugandroid/levels/InitLevel.kt

@@ -13,9 +13,15 @@ internal fun initLevel(): Level = level(
     description = "A new directory, `git_hug`, has been created; initialize an empty repository in it.",
     hints = listOf("You can type `git --help` or `git` in your shell to get a list of available git commands."),
     commandSuggestions = listOf("git init", "git status"),
-    setup = { RepoState() },
+    setup = { RepoState(currentDir = "git_hug") },
     validator = repoPredicate { it.initialized },
     testCases = listOf(
         levelTestCase("plain init", "git init"),
     ),
+    setupChecks = listOf(
+        levelSetupCheck(
+            name = "starts in git_hug",
+            failureMessage = "Expected the learner to start in the created git_hug directory.",
+        ) { repo -> repo.currentDir == "git_hug" && !repo.initialized },
+    ),
 )