fix: comprehensive script audit - bug fixes and optimizations

- ct/invidious.sh: fix copy-paste bug (OxiCloud code in update block)
- install/invidious-install.sh: fix sed redirect, service filename mismatch
- ct/forgejo-runner.sh: fix binary download path, bump Debian to 13
- ct/authentik.sh: add -f flag to curl (fail on HTTP errors)
- ct/localagi.sh: add -f flag to curl, add installation check guard
- ct/ente.sh: fix broken install check (/var -> /opt/ente), apt-get -> apt
- ct/garmin-grafana.sh: add explicit tarball mode to fetch_and_deploy
- install/garmin-grafana-install.sh: fix local outside function, add tarball mode
- install/ente-install.sh: uncomment cleanup_lxc
- install/github-runner-install.sh: add missing , fix msg_info text
- ct/step-ca.sh: remove duplicate success message
- ct/devuan.sh, ct/ubuntu.sh: apt-get -> apt, remove duplicate msg_ok

install/ente-install.sh

@@ -350,4 +350,4 @@ msg_ok "Created helper scripts"
 
 motd_ssh
 customize
-#cleanup_lxc
+cleanup_lxc