Fix Git editor reword workflow and UI coverage

- show Git editor file paths instead of the submitted git command
- surface follow-up commit message editors during interactive rebase reword
- add rename-commit UI tests for editor and amend-message solution paths
- add broader embedded level solution scenarios for alternate Git workflows

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

@@ -46,6 +46,7 @@ internal fun findOldBranchLevel(): Level = level(
     validator = repoPredicate { repo -> repo.headBranch == "solve_world_hunger" },
     testCases = listOf(
         levelTestCase("checkout old branch", "git checkout solve_world_hunger"),
+        levelTestCase("switch old branch", "git switch solve_world_hunger"),
     ),
     setupChecks = listOf(
         levelSetupCheck(