refactor: 推进后端分层架构治理

tests/test_plugin_registry.py

@@ -0,0 +1,38 @@
+from types import SimpleNamespace
+
+from app.runtime.extensions.plugin.registry import PluginRegistry
+
+
+def test_registry_owns_classes_instances_and_stable_snapshots():
+    """注册表集中持有类与实例，快照不受后续热重载修改影响。"""
+    registry = PluginRegistry()
+    plugin_class = type("Demo", (), {})
+    plugin_instance = SimpleNamespace(plugin_name="演示")
+    registry.classes["Demo"] = plugin_class
+    registry.running["Demo"] = plugin_instance
+
+    snapshot = registry.running_snapshot()
+    registry.running["Other"] = SimpleNamespace(plugin_name="其它")
+
+    assert registry.has_class("Demo")
+    assert registry.plugin_class("Demo") is plugin_class
+    assert registry.instance("Demo") is plugin_instance
+    assert registry.plugin_ids() == ["Demo"]
+    assert registry.running_ids() == ["Demo", "Other"]
+    assert list(snapshot) == ["Demo"]
+
+
+def test_registry_clear_preserves_compatibility_mapping_identity():
+    """整体停止插件时原地清空，旧调用方持有的字典引用继续有效。"""
+    registry = PluginRegistry()
+    classes = registry.classes
+    running = registry.running
+    classes["Demo"] = object()
+    running["Demo"] = object()
+
+    registry.clear()
+
+    assert registry.classes is classes
+    assert registry.running is running
+    assert classes == {}
+    assert running == {}