进一步实现 interface

src/heurams/kernel/particles/__init__.py

@@ -1,7 +1,7 @@
 from .electron import Electron
 from .nucleon import Nucleon
 from .orbital import Orbital
-from .atom import Atom
+from .atom import Atom, atom_registry
 from .probe import probe_all, probe_by_filename
 from .loader import load_nucleon, load_electron
 
@@ -14,4 +14,5 @@ __all__ = [
     "probe_by_filename",
     "load_nucleon",
     "load_electron",
+    "atom_registry",
 ]