Update restaurant finder README: add curl command to actually invoke model. (#1232)

* Update README.md

* Update samples/agent/adk/restaurant_finder/README.md

Author: polina-c

samples/agent/adk/restaurant_finder/README.md

@@ -29,11 +29,32 @@ This sample uses the Agent Development Kit (ADK) along with the A2A protocol to
     uv run .
     ```
 
-4. In another terminal window, verify that the agent is available via A2A:
-
-    ```bash
-    curl http://localhost:10002/.well-known/agent-card.json
-    ```
+4. In another terminal window:
+
+    * verify that the agent is available via A2A:
+
+        ```bash
+        curl http://localhost:10002/.well-known/agent-card.json
+        ```
+    
+    * send a message to the agent:
+
+        ```bash
+        curl http://localhost:10002 \
+          -H 'Content-Type: application/json' \
+          -d '{
+            "jsonrpc": "2.0",
+            "id": 1,
+            "method": "message/send",
+            "params": {
+              "message": {
+                "role": "user",
+                "parts": [{"text": "Find me an Italian restaurant"}],
+                "messageId": "1"
+              }
+            }
+          }'
+        ```
 
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