Enhance 5G modem management with integrated web GUI and connection control

- Introduced a web GUI for managing 5G connections, replacing the standalone 5g-router service.
- Updated scripts to ensure exclusive access to the AT port, preventing conflicts.
- Improved troubleshooting documentation in 5G_MODEM_TROUBLESHOOTING.md, adding checks for processes using the AT port.
- Enhanced connection management in the web app, including auto-connect and detailed status APIs.
- Updated installation scripts to reflect changes in service management and dependencies.

etc/init.d/5g-webgui

@@ -1,8 +1,11 @@
 #!/sbin/openrc-run
-# Alpine 5G Router – Web GUI (Flask). Login: admin/support with different permissions.
-# Rev: 1  (see REVISION in repo root)
+# Alpine 5G Router – Web GUI with integrated 5G connection management.
+# Rev: 2  (see REVISION in repo root)
+#
+# This service now handles both the Web GUI and 5G modem connection.
+# The standalone 5g-router service is no longer needed.
 
-description="5G Router Web GUI (port 5000)"
+description="5G Router Web GUI with connection management (port 5000)"
 command="/usr/local/share/5g-webgui/run.sh"
 command_background="yes"
 pidfile="/run/5g-webgui.pid"
@@ -12,6 +15,7 @@ error_log="/var/log/5g-webgui.log"
 depend() {
     need net
     after bootmisc
+    # Note: 5g-router service is no longer needed; connection is managed by this service
 }
 
 start_pre() {
@@ -20,8 +24,12 @@ start_pre() {
         return 1
     fi
     if ! command -v python3 >/dev/null 2>&1; then
-        eend 1 "python3 not found. Install: apk add python3 py3-flask"
+        eend 1 "python3 not found. Install: apk add python3 py3-flask py3-serial"
         return 1
     fi
+    # Ensure pyserial is available
+    if ! python3 -c "import serial" 2>/dev/null; then
+        ewarn "pyserial not found. Install: pip install pyserial"
+    fi
     return 0
 }