feat(skill): finish n8n webhook skill

skills/n8n-webhook/references/payloads.md

@@ -33,6 +33,9 @@ Purpose:
 - keep the external n8n surface small
 - route several agent-safe operations behind one authenticated webhook
 
+Shipped workflow asset:
+- `assets/openclaw-action.workflow.json`
+
 Recommended request shape:
 
 ```json
@@ -87,6 +90,9 @@ Request:
 Purpose:
 - append a short line to a known log or tracking sink
 
+Sample payload file:
+- `assets/test-append-log.json`
+
 ### `notify`
 
 Request:
@@ -104,6 +110,9 @@ Request:
 Purpose:
 - send a small notification through a known downstream channel
 
+Sample payload file:
+- `assets/test-notify.json`
+
 ## Naming guidance
 
 - Use lowercase kebab-case for webhook paths.