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.

docs/WEBGUI.md

@@ -2,6 +2,14 @@
 
 Web interface with login and role-based access (admin and support). **One HTML page per function** (Status, Logs, Restart 5G, Config, Firewall, Routes, Users) with shared navigation.
 
+**As of Rev 2, the Web GUI includes integrated 5G connection management.** It now handles:
+- Modem AT commands via native Python (pyserial)
+- 5G connection lifecycle (connect, disconnect, reconnect)
+- Watchdog for automatic reconnection
+- NAT/firewall configuration
+
+The standalone `5g-router` service is no longer needed; `5g-webgui` is the recommended single service.
+
 ## Access
 
 - **URL:** `http://<device-ip>:5000` (e.g. `http://10.130.60.121:5000`)
@@ -18,6 +26,7 @@ Web interface with login and role-based access (admin and support). **One HTML p
 | View status        | ✓     | ✓      |
 | View logs          | ✓     | ✓      |
 | Restart 5G         | ✓     | ✓      |
+| Connect/Disconnect | ✓     | ✓      |
 | Edit config        | ✓     | –      |
 | Edit firewall      | ✓     | –      |
 | View routes        | ✓     | –      |
@@ -28,8 +37,9 @@ Web interface with login and role-based access (admin and support). **One HTML p
 ### On the device (after main install)
 
 ```bash
-# Install Python and Flask (Alpine)
+# Install Python, Flask, and pyserial (Alpine)
 apk add python3 py3-flask
+pip install pyserial
 
 # If you used scripts/install.sh, Web GUI is already under /usr/local/share/5g-webgui
 # Enable and start the service:
@@ -44,11 +54,36 @@ cd /usr/local/share/5g-webgui && ./run.sh
 
 ```bash
 cd web
-pip install -r requirements.txt   # or: apk add py3-flask
+pip install -r requirements.txt   # Flask and pyserial
 python3 app.py
 # Open http://localhost:5000
 ```
 
+## API Endpoints for 5G Control
+
+| Endpoint | Method | Description |
+|----------|--------|-------------|
+| `/api/status` | GET | Connection status + modem info |
+| `/api/5g/status` | GET | Detailed connection status |
+| `/api/5g/connect` | POST | Manually connect 5G |
+| `/api/5g/disconnect` | POST | Manually disconnect 5G |
+| `/api/5g/restart` | POST | Disconnect then reconnect |
+
+## Architecture
+
+```
+5g-webgui service
+    ├── Flask App (port 5000)
+    ├── ATClient (pyserial → /dev/ttyUSB1)
+    └── ConnectionManager
+        ├── connect() - APN, PDP, IP, NAT
+        ├── disconnect()
+        ├── check_health()
+        └── watchdog_loop() (background thread)
+```
+
+The connection auto-starts when the service starts (on first web request). If `WATCHDOG_INTERVAL` is set in `/etc/5g-router.conf`, a background thread periodically checks connection health and reconnects if needed.
+
 ## Security
 
 - Set **SECRET_KEY** in production: `export SECRET_KEY="your-random-secret"` before starting the app (or in the OpenRC service).