feat: Clickable stat tiles, view toggle, CPU/memory metrics, restore fix

- Dashboard stat tiles (Services/Healthy/Down) switch to filtered table view
- Card/Table view toggle in topbar with filter badges
- System page: CPU usage bar, memory/swap bars from /proc, filtered to real disks
- Fix restore.py: offsite download → offsite restore (correct ops CLI command)
- Dockerfile: add libexpat1 for host venv compatibility in restore flows
- Remove separate Services sidebar item (merged into Dashboard)

	Dockerfile	diff | view | blame | history
	app/app/routers/restore.py	diff | view | blame | history
	app/app/routers/system.py	diff | view | blame | history
	app/routers/restore.py	diff | view | blame | history
	app/routers/services.py	diff | view | blame | history
	app/routers/system.py	diff | view | blame | history
	static/index.html	diff | view | blame | history
	static/js/app.js	diff | view | blame | history