Mark tasks as experimental in architecture docs

Author: LucaButBoring

docs/docs/learn/architecture.mdx

@@ -134,7 +134,7 @@ For more details about client primitives see [client concepts](./client-concepts
 
 Besides server and client primitives, the protocol offers cross-cutting utility primitives that augment how requests are executed:
 
-- **Tasks**: Asynchronous execution wrappers that enable deferred result retrieval and status tracking for any MCP request (e.g., long-running computations, workflow automation, batch processing, multi-step operations)
+- **Tasks (Experimental)**: Asynchronous execution wrappers that enable deferred result retrieval and status tracking for any MCP request (e.g., expensive computations, workflow automation, batch processing, multi-step operations)
 
 #### Notifications