fix: install git for durable state recovery

tests/test_super_agent.py

@@ -20,6 +20,7 @@ from hf_discovery import HuggingFaceDiscovery, parse_model_card_front_matter  #
 from official_capabilities import OfficialCapabilityRegistry  # noqa: E402
 from routing_engine import SuccessFirstRoutingEngine  # noqa: E402
 from state_sync import StateGitSync  # noqa: E402
+from state_sync import StateSyncError  # noqa: E402
 
 
 class OfficialClient:
@@ -207,6 +208,19 @@ class SuperAgentTests(unittest.TestCase):
                     )
                 )
 
+    def test_missing_git_has_actionable_state_sync_error(self) -> None:
+        with tempfile.TemporaryDirectory() as temporary_dir:
+            manager = StateGitSync(
+                project_root=Path(temporary_dir),
+                credentials={"username": "u", "email": "e@example.com", "password": "p"},
+                remote="unused",
+                log_fn=lambda _: None,
+            )
+            with patch("state_sync.subprocess.run", side_effect=FileNotFoundError("git")):
+                with self.assertRaisesRegex(StateSyncError, "rebuild the service image"):
+                    manager._git("version")
+            manager.close()
+
     def test_config_patch_requires_repeated_cross_model_success(self) -> None:
         with tempfile.TemporaryDirectory() as temporary_dir:
             root = Path(temporary_dir)