Require native Git runtime and bundle full manpages

- Remove the app fallback path when native Git is unavailable and show a startup blocker instead
- Fix native level setup for staged file counting and cherry-pick parity
- Improve manpage loading/search and bundle full Git documentation assets
- Integrate Git cross-compilation into AndroidProjectTooling.sh and remove debug AAB support

app/src/test/java/solutions/tretter/githugandroid/GitSandboxEngineTest.kt

@@ -276,6 +276,16 @@ class GitSandboxEngineTest {
         assertFalse(updatedRepo.files.any { it.name == "deleteme.txt" })
     }
 
+    @Test
+    fun interactiveStageDoesNotThrow() {
+        val repo = RepoState(initialized = true, files = listOf(GitFile("README")))
+
+        val (updatedRepo, output) = GitSandboxEngine.execute(repo, "git stage -i")
+
+        assertEquals(repo, updatedRepo)
+        assertTrue(output.any { it.contains("Interactive staging is not supported") })
+    }
+
     private fun testGitBinary(): File {
         System.getenv("GITHUG_TEST_GIT_BINARY")
             ?.takeIf { it.isNotBlank() }