Releases on Gitea, one-line installer and auto-update (1.1.0)

- .github/workflows/release.yml: a tag vX.Y.Z runs the tests, publishes
  daynivo-kiosk-os-X.Y.Z.tar.gz (+ .sha256) and install-online.sh as a
  Gitea release, then builds the SD image with pi-gen and attaches it.
- install-online.sh: curl | sudo bash installer for the latest release.
- voxip-kiosk-updater: checks the latest release, verifies and unpacks a
  newer one under /opt/daynivo-kiosk-os and runs its update.sh. A daily
  timer checks around 03:00 and installs when auto_update is on.
- Web interface: Systeem -> Software-updates with the auto-update switch,
  check now and install now (helper verbs update-check / update-install).
- CI checks out with plain git, so it runs on Gitea's act_runner too.

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

uninstall.sh

@@ -17,7 +17,7 @@ PURGE=0
 
 UNITS=(voxip-kiosk-healthcheck.timer voxip-kiosk-healthcheck.service voxip-kiosk-agent.service
        voxip-kiosk-browser.service voxip-kiosk-x.service voxip-kiosk-manager.service
-       voxip-network-guard.service voxip-boot-import.service)
+       voxip-network-guard.service voxip-boot-import.service voxip-kiosk-update.timer voxip-kiosk-update.service)
 
 PREVIOUS_TARGET="$(cat /var/lib/voxip-kiosk/previous-default-target 2>/dev/null || true)"
 PREVIOUS_SPLASH="$(cat /var/lib/voxip-kiosk/previous-plymouth-theme 2>/dev/null || true)"
@@ -57,6 +57,8 @@ fi
 if [[ $PURGE -eq 1 ]]; then
   echo "==> Configuratie, status, logs en gebruikers verwijderen"
   rm -rf /etc/voxip-kiosk /var/lib/voxip-kiosk /var/lib/voxip-kiosk-network /var/lib/voxip-kiosk-browser /var/log/voxip-kiosk
+  # Downloaded releases (install-online.sh and the updater); safe even when running from there.
+  rm -rf /opt/daynivo-kiosk-os /var/cache/voxip-kiosk
   rm -f /etc/NetworkManager/system-connections/voxip-eth0.nmconnection /etc/NetworkManager/system-connections/voxip-wlan0.nmconnection
   nmcli connection reload 2>/dev/null || true
   userdel -r kiosk 2>/dev/null || true