feat(sizer-receiver): ✨ add GARM WebSocket event enrichment env vars

Add GARM_URL, GARM_USER, and GARM_PASSWORD environment variables to
the sizer-receiver deployment so it can connect to GARM's WebSocket
event stream for run-status enrichment.

Ref: IPCEICIS-8514

otc/dev.t09.de/stacks/garm/sizer-receiver/deployment.yaml

@@ -39,6 +39,15 @@ spec:
                 secretKeyRef:
                   name: sizer-tokens
                   key: hmac-key
+            - name: GARM_URL
+              value: "http://garm.garm.svc.cluster.local:80"
+            - name: GARM_USER
+              value: "admin"
+            - name: GARM_PASSWORD
+              valueFrom:
+                secretKeyRef:
+                  name: garm-fixed-credentials
+                  key: admin_password
           volumeMounts:
             - name: data
               mountPath: /data