fix(dream): restore cursor with memory state

Track the Dream cursor in memory versioning so restores do not skip history after rolling back Dream commits.

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/agent/test_memory_store.py

@@ -5,7 +5,7 @@ from datetime import datetime
 
 import pytest
 
-from nanobot.agent.memory import MemoryStore, _HISTORY_ENTRY_HARD_CAP
+from nanobot.agent.memory import _HISTORY_ENTRY_HARD_CAP, MemoryStore
 
 
 @pytest.fixture
@@ -241,6 +241,26 @@ class TestDreamCursor:
         store2 = MemoryStore(store.workspace)
         assert store2.get_last_dream_cursor() == 3
 
+    def test_git_restore_rolls_back_dream_cursor(self, tmp_path):
+        store = MemoryStore(tmp_path)
+        store.write_memory("before")
+        store.set_last_dream_cursor(1)
+        assert store.git.init() is True
+
+        store.write_memory("after")
+        store.set_last_dream_cursor(2)
+        dream_sha = store.git.auto_commit("dream: update")
+        assert dream_sha is not None
+
+        store.write_memory("newer")
+        store.set_last_dream_cursor(3)
+
+        restore_sha = store.git.revert(dream_sha)
+
+        assert restore_sha is not None
+        assert store.read_memory() == "before"
+        assert store.get_last_dream_cursor() == 1
+
 
 class TestLegacyHistoryMigration:
     def test_read_unprocessed_history_handles_entries_without_cursor(self, store):