fix(blocky): restart on failure and wait for network-online (#17601)

The systemd service unit created by install/blocky-install.sh has
After=network.target and no restart policy. On a container where blocky
binds to a static IP and the interface is not yet configured when the
unit starts, blocky exits once with "bind: cannot assign requested
address" and stays dead. This was observed on Debian 13 LXC / PVE 9
after a host reboot: internal DNS was down until a manual restart.

Two fixes:

1. [Unit] After=/Wants=network-online.target: standard ordering,
prevents the start before the network is usable where a wait-online
provider exists.

2. [Service] Restart=on-failure + RestartSec=5: matches the existing
Restart=on-failure in install/traefik-install.sh; the 5s spacing also
overrides systemd's default start-rate limit (5 starts / 10 s) from
ending retries.

Verification:

1. Container reboot → blocky active with no manual intervention

2. SIGKILL → auto-restart within the restart interval

Co-authored-by: Fidel Ramos <contact.gyldd@8shield.net>

install/blocky-install.sh

@@ -67,11 +67,16 @@ msg_info "Creating Service"
 cat <<EOF >/etc/systemd/system/blocky.service
 [Unit]
 Description=Blocky
-After=network.target
+After=network-online.target
+Wants=network-online.target
+
 [Service]
 User=root
 WorkingDirectory=/opt/blocky
+Restart=on-failure
+RestartSec=5
 ExecStart=/opt/blocky/./blocky --config config.yml
+
 [Install]
 WantedBy=multi-user.target
 EOF