navidrome: restore data folder ownership on install and update

Upstream's deb postinstall runs chown navidrome:navidrome on
/var/lib/navidrome/cache without -R, and only behind an .installed
flag, so it never runs again on an upgrade. Every navidrome command
the packaging invokes as root creates cache content owned by root,
which the service then cannot write as the navidrome user - artwork
that was already cached keeps working while newly resolved album and
playlist covers fail.

Reassert ownership of the data folder after deploying the release.
The music folder is left alone, it is commonly a bind mount.

install/navidrome-install.sh

@@ -19,6 +19,10 @@ msg_ok "Installed Dependencies"
 
 fetch_and_deploy_gh_release "navidrome" "navidrome/navidrome" "binary"
 
+if id -u navidrome >/dev/null 2>&1; then
+  chown -R navidrome:navidrome /var/lib/navidrome
+fi
+
 msg_info "Starting Navidrome"
 systemctl enable -q --now navidrome
 msg_ok "Started Navidrome"