webui: fix rendering for gh worfkow events
diff --git a/webui/src/web-components/sketch-external-message.ts b/webui/src/web-components/sketch-external-message.ts
index 1df27d8..03f6dbd 100644
--- a/webui/src/web-components/sketch-external-message.ts
+++ b/webui/src/web-components/sketch-external-message.ts
@@ -46,7 +46,8 @@
           >${run.workflow.name} -
           ${run.workflow_run.conclusion || run.workflow_run.status}</span
         >
-        on ${run.workflow_run.head_branch} at ${run.workflow_run.head_commit}`;
+        on ${run.workflow_run.head_branch} at
+        ${run.workflow_run.head_sha.substring(0, 7)}`;
 
       this.detailsContent = html`
         <div class="flex items-center gap-2">