feat(actions): add action context for safe nested dispatch with depth limit to prevent deadlocks

ts/smartstate.classes.stateaction.ts

@@ -1,7 +1,16 @@
 import { StatePart } from './smartstate.classes.statepart.js';
 
+/**
+ * Context object passed to action definitions, enabling safe nested dispatch.
+ * Use `context.dispatch()` to dispatch sub-actions inline (bypasses the mutation queue).
+ * Direct `statePart.dispatchAction()` from within an action will deadlock.
+ */
+export interface IActionContext<TStateType> {
+  dispatch<T>(action: StateAction<TStateType, T>, payload: T): Promise<TStateType>;
+}
+
 export interface IActionDef<TStateType, TActionPayloadType> {
-  (stateArg: StatePart<any, TStateType>, actionPayload: TActionPayloadType): Promise<TStateType>;
+  (stateArg: StatePart<any, TStateType>, actionPayload: TActionPayloadType, context?: IActionContext<TStateType>): Promise<TStateType>;
 }
 
 /**