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/main/java/solutions/tretter/githugandroid/levels/RmLevel.kt

@@ -14,7 +14,7 @@ internal fun rmLevel(): Level = level(
     hints = emptyList(),
     commandSuggestions = listOf("git status", "git rm deleteme.rb"),
     setup = { RepoState(initialized = true, files = listOf(GitFile("deleteme.rb", tracked = true, deleted = true)), commits = listOf(CommitNode("0000001", "Added a temp file")), branches = mapOf("master" to 1)) },
-    validator = repoPredicate { repo -> repo.files.none { it.name == "deleteme.rb" } },
+    validator = repoPredicate { repo -> repo.files.none { it.name == "deleteme.rb" && !it.deleted } || repo.files.any { it.name == "deleteme.rb" && it.deleted && it.staged } },
     testCases = listOf(
         levelTestCase("git rm deleted path", "git rm deleteme.rb"),
     ),