fix: update minimal MultiAgentRouter example and documentation

examples/multi_agent/mar/multi_agent_router_minimal.py

@@ -1,19 +1,25 @@
-from swarms import Agent, MultiAgentRouter
+from swarms import Agent
+from swarms.structs.swarm_router import SwarmRouter
 
-if __name__ == "__main__":
-    agents = [
-        Agent(
-            agent_name="Researcher",
-            system_prompt="Answer questions briefly.",
-            model_name="gpt-4o-mini",
-        ),
-        Agent(
-            agent_name="Coder",
-            system_prompt="Write small Python functions.",
-            model_name="gpt-4o-mini",
-        ),
-    ]
+agents = [
+    Agent(
+        agent_name="Researcher",
+        system_prompt="Answer questions briefly.",
+        model_name="gpt-4o-mini",
+    ),
+    Agent(
+        agent_name="Coder",
+        system_prompt="Write small Python functions.",
+        model_name="gpt-4o-mini",
+    ),
+]
 
-    router = MultiAgentRouter(agents=agents)
+router = SwarmRouter(
+    name="multi-agent-router-demo",
+    description="Routes tasks to the most suitable agent",
+    agents=agents,
+    swarm_type="MultiAgentRouter"
+)
 
-    result = router.route_task("Write a function that adds two numbers")
+result = router.run("Write a function that adds two numbers")
+print(result)