fix(systemd): wait for network connectivity before starting services

Change After=network.target to After=network-online.target + Wants=network-
online.target in both service templates and install_web_service.sh.

network.target only means NetworkManager has started — it does NOT mean the
device has an active internet connection. On boot, the LED matrix service was
starting within seconds of the network interface appearing, before WiFi
association and DHCP completed, causing all first-update API calls to fail
with "Network is unreachable" or DNS resolution errors.

network-online.target waits for a confirmed network route before the service
starts. On Raspberry Pi OS this is provided by NetworkManager-wait-online.
The tradeoff is a few extra seconds at boot, which is acceptable for a
display device.

Applied live to /etc/systemd/system/ledmatrix.service on devpi via
systemctl daemon-reload (no restart required for the config change to take
effect on next boot).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

systemd/ledmatrix.service

@@ -1,6 +1,7 @@
 [Unit]
 Description=LED Matrix Display Service
-After=network.target
+After=network-online.target
+Wants=network-online.target
 
 [Service]
 Type=simple