Add web GUI, docs, scripts, and 5G router config

- Web app (Flask): status, config, firewall, logs, users, restart
- Docs: AT commands, deploy, DNS, quickstart, web GUI
- Scripts: connect, deploy, diag, healthcheck, modem-status, speedtest, status, troubleshoot
- Init and iptables: 5g-router, 5g-webgui, rules.v4
- CHANGELOG, TODO, REVISION; config and README updates

scripts/ssh-diag-modem.sh

@@ -0,0 +1,26 @@
+#!/bin/sh
+# Alpine 5G Router – run modem diagnostics on device via SSH
+# Usage: ./scripts/ssh-diag-modem.sh [user@host]
+# Or:    TARGET=root@192.168.1.1 ./scripts/ssh-diag-modem.sh
+
+TARGET="${1:-${TARGET:-root@10.130.60.121}}"
+SSH_OPTS="${SSH_OPTS:--o ConnectTimeout=10}"
+
+echo "Running modem diagnostics on $TARGET"
+echo ""
+
+ssh $SSH_OPTS "$TARGET" "
+  echo '========== diag-modem-up.sh =========='
+  if [ -x /usr/local/bin/diag-modem-up.sh ]; then
+    /usr/local/bin/diag-modem-up.sh
+  else
+    echo 'Not installed. Deploy first: ./scripts/deploy.sh $TARGET'
+    echo 'Then re-run this script.'
+    exit 1
+  fi
+  echo ''
+  echo '========== diag-at-port.sh =========='
+  if [ -x /usr/local/bin/diag-at-port.sh ]; then
+    /usr/local/bin/diag-at-port.sh
+  fi
+"