Add daily app-token renewal (script + systemd timer)

Periodic scoped tokens (~/.config/openbao/*.token) expired because nothing
renewed them within their period. renew-app-tokens.sh renews all of them via
auth/token/renew-self; openbao-token-renew.timer runs it daily (Persistent=true).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

systemd/openbao-token-renew.service

@@ -0,0 +1,12 @@
+[Unit]
+Description=Renew scoped OpenBAO app tokens so periodic tokens never lapse
+After=network-online.target docker.service
+Wants=network-online.target
+Requires=docker.service
+
+[Service]
+Type=oneshot
+User=lutz
+Group=lutz
+ExecStart=/home/lutz/Projects/OpenBAO/scripts/renew-app-tokens.sh
+# Renews ~/.config/openbao/*.token via auth/token/renew-self. Best-effort.