refactor(automations): vertical-slice actions and triggers by domain

surfsense_backend/app/automations/actions/__init__.py

@@ -1 +1,24 @@
-"""Action implementations. One subpackage per built-in action type."""
+"""Actions domain: registry surface + built-in action packages.
+
+Each action lives in its own subpackage (``agent_task/``, ...) and self-registers
+at import time via its ``definition`` module. Side-effect imports below ensure
+the registry is populated whenever anyone touches the actions package.
+"""
+
+from __future__ import annotations
+
+from .store import all_actions, get_action, register_action
+from .types import ActionContext, ActionDefinition, ActionHandler, ActionHandlerFactory
+
+__all__ = [
+    "ActionContext",
+    "ActionDefinition",
+    "ActionHandler",
+    "ActionHandlerFactory",
+    "all_actions",
+    "get_action",
+    "register_action",
+]
+
+# Built-in actions self-register at import time.
+from . import agent_task  # noqa: E402, F401