v0.4+v0.5: TUI dashboard, tab completion, systemd, Docker, process isolation

- New: services/sysmon_widget.py (CPU/MEM/DISK/NET real-time)
- Enhanced: tui_service.py (4-section layout, plugin status panel)
- Enhanced: command_service.py + tui (Tab completion)
- New: deploy/sensu.service (systemd)
- New: deploy/Dockerfile (Alpine, 4200+4240)
- New: services/process_isolated.py (multiprocess plugin isolation)
- Tests: 23/23 passing

deploy/sensu.service

@@ -0,0 +1,18 @@
+[Unit]
+Description=SenSu Plugin Framework
+After=network.target
+
+[Service]
+Type=simple
+User=aska
+WorkingDirectory=/data/data/com.termux/files/home/Proj/SenSu_workspace
+ExecStart=/data/data/com.termux/files/usr/bin/python3 /data/data/com.termux/files/home/Proj/SenSu_workspace/start.py --headless
+Restart=on-failure
+RestartSec=5
+Environment=SENSU_ADMIN_PASSWORD=changeme
+Environment=SENSU_API_PASSWORD=changeme
+Environment=SENSU_PANEL_USER=admin
+Environment=SENSU_PANEL_PASS=changeme
+
+[Install]
+WantedBy=multi-user.target