ci(pegasus): relax test agent placement

Jenkinsfile

@@ -6,7 +6,7 @@ pipeline {
 apiVersion: v1
 kind: Pod
 spec:
-  nodeSelector: {hardware: rpi5, kubernetes.io/arch: arm64, node-role.kubernetes.io/worker: "true"}
+  nodeSelector: {kubernetes.io/arch: arm64, node-role.kubernetes.io/worker: "true"}
   affinity:
     nodeAffinity:
       requiredDuringSchedulingIgnoredDuringExecution:
@@ -485,6 +485,7 @@ PY
   post {
     always {
       script {
+        try {
           if (fileExists('build/junit-backend.xml') || fileExists('build/junit-frontend.xml')) {
             try {
               junit allowEmptyResults: true, testResults: 'build/junit-backend.xml,build/junit-frontend.xml'
@@ -492,8 +493,25 @@ PY
               echo "junit step unavailable: ${err.class.simpleName}"
             }
           }
+        } catch (Throwable err) {
+          if (err.class.simpleName == 'MissingContextVariableException') {
+            echo 'workspace unavailable; skipping junit publish'
+          } else {
+            throw err
           }
+        }
+      }
+      script {
+        try {
           archiveArtifacts artifacts: 'build/**', allowEmptyArchive: true, fingerprint: true
+        } catch (Throwable err) {
+          if (err.class.simpleName == 'MissingContextVariableException') {
+            echo 'workspace unavailable; skipping artifact archive'
+          } else {
+            throw err
+          }
+        }
+      }
     }
   }
 }