chore: track project memory files in git

.gitignore

@@ -30,4 +30,6 @@ __pycache__/
 .mypy_cache/
 
 # Local project memory/state
-.memory/
+# Keep memory files tracked
+!.memory/
+!.memory/**

.memory/todo.md

@@ -0,0 +1,6 @@
+# Todo
+
+- Improve failure-path coverage for write operations.
+- Verify and harden nested group path resolution.
+- Keep integration write tests on temporary copies only.
+- Keep API minimal and predictable.