Add the jarld.service alias for jarl.service

systemctl restart/status jarld now work too. The package relinks a unit
enabled by an older version on upgrade, so the alias appears without
re-enabling; make uninstall removes the link.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

deploy/debian/postinst

@@ -38,6 +38,13 @@ if [ "$1" = configure ]; then
 		if systemctl is-enabled --quiet jarl-backup.timer 2>/dev/null; then
 			systemctl start jarl-backup.timer || true
 		fi
+		# The jarld.service alias is linked when jarl.service is enabled;
+		# relink a unit enabled before the alias existed (this neither
+		# starts nor stops jarld).
+		if [ -n "$2" ] && systemctl is-enabled --quiet jarl.service 2>/dev/null \
+			&& [ ! -e /etc/systemd/system/jarld.service ]; then
+			systemctl reenable jarl.service >/dev/null 2>&1 || true
+		fi
 		# An upgrade restarts a running jarld (its database is upgraded
 		# when it starts). A first install starts nothing: Jarl needs
 		# 'jarld init' and 'jarld adopt' first.