Align level parity docs and fetch/status validation

- Add LevelsCompare.md with setup and validation comparisons against Gazler/githug.
- Document that LevelsCompare.md must be updated when level behavior changes.
- Track FETCH_HEAD count in RepoState so the Fetch level can match upstream validation.
- Mirror upstream Status setup with staged files plus untracked database.yml.
- Keep Fetch from being solved by pull despite native Git FETCH_HEAD behavior.
- Bump app version and build debug APK.

app/src/main/java/solutions/tretter/githugandroid/RepoStateSaver.kt

@@ -20,6 +20,7 @@ val RepoStateSaver = listSaver<RepoState, Any>(
             state.pushedTags.toList(),
             state.submodules.flatMap { listOf(it.key, it.value) },
             state.maintenanceActions.toList(),
+            state.fetchHeadCount,
         )
     },
     restore = { saved ->
@@ -37,6 +38,7 @@ val RepoStateSaver = listSaver<RepoState, Any>(
         val pushedTags = saved.getOrNull(12) as? List<*> ?: emptyList<Any>()
         val submoduleParts = saved.getOrNull(13) as? List<*> ?: emptyList<Any>()
         val maintenanceActions = saved.getOrNull(14) as? List<*> ?: emptyList<Any>()
+        val fetchHeadCount = saved.getOrNull(15) as? Int ?: 0
         RepoState(
             initialized = initialized,
             headBranch = headBranch,
@@ -59,6 +61,7 @@ val RepoStateSaver = listSaver<RepoState, Any>(
             config = configParts.chunked(2).associate { (it[0] as String) to (it[1] as String) },
             stashes = stashes.filterIsInstance<String>(),
             fetchedBranches = fetchedBranches.filterIsInstance<String>().toSet(),
+            fetchHeadCount = fetchHeadCount,
             pushedBranches = pushedBranches.filterIsInstance<String>().toSet(),
             pushedTags = pushedTags.filterIsInstance<String>().toSet(),
             submodules = submoduleParts.chunked(2).associate { (it[0] as String) to (it[1] as String) },