feat: Add container restart functionality from web UI

- Added restart button to settings page
- Created /api/restart endpoint (file-flag based)
- Implemented watch-restart.sh daemon
- Added systemd service for restart watcher
- Updated README with restart setup instructions
- Container automatically restarts when settings changed

Settings flow:
1. User edits settings in web UI
2. Click 'Save Settings' to persist to .env
3. Click 'Restart Bot' to apply changes
4. Watcher detects flag and restarts container
5. New settings loaded automatically

trading-bot-restart-watcher.service

@@ -0,0 +1,17 @@
+[Unit]
+Description=Trading Bot v4 Container Restart Watcher
+After=docker.service
+Requires=docker.service
+
+[Service]
+Type=simple
+User=root
+WorkingDirectory=/home/icke/traderv4
+ExecStart=/home/icke/traderv4/watch-restart.sh
+Restart=always
+RestartSec=10
+StandardOutput=append:/home/icke/traderv4/logs/restart-watcher.log
+StandardError=append:/home/icke/traderv4/logs/restart-watcher.log
+
+[Install]
+WantedBy=multi-user.target