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/GameModels.kt

@@ -31,6 +31,7 @@ data class RepoState(
     val config: Map<String, String> = emptyMap(),
     val stashes: List<String> = emptyList(),
     val fetchedBranches: Set<String> = emptySet(),
+    val fetchHeadCount: Int = 0,
     val pushedBranches: Set<String> = emptySet(),
     val pushedTags: Set<String> = emptySet(),
     val submodules: Map<String, String> = emptyMap(),
@@ -55,4 +56,3 @@ data class LevelTestCase(
 )
 
 fun sampleLevels(): List<Level> = allGithugLevels()
-