Argo CD only substitutes $secret:key references from Secrets carrying
the label app.kubernetes.io/part-of: argocd. Without it, the server
logs "secret key does not exist in secret" and renders placeholders
verbatim into the OIDC redirect URL.
Adding the label to the SealedSecret template ensures sealed-secrets-
controller re-produces the Secret with the label on every restore, so
OIDC keeps working after DR / re-seal.
Co-Authored-By: Paperclip <noreply@paperclip.ing>