Add printer status badges, remove SpoolBuddy inventory page

- Add printer status badges to dashboard left column (green/gray
    online/offline dots, compact wrapping pills, overflow-hidden)
  - Remove SpoolBuddy inventory page — inventory management belongs
    in the main Bambuddy frontend, not the kiosk
  - Remove inventory nav item from bottom nav (now 3 tabs)
  - Replace "Add to Inventory" navigate with quick-add modal that
    creates a basic PLA spool entry via API, with a hint to use
    the main Bambuddy UI for full spool details instead

frontend/src/components/spoolbuddy/SpoolBuddyBottomNav.tsx

@@ -22,16 +22,6 @@ const navItems = [
       </svg>
     ),
   },
-  {
-    to: '/spoolbuddy/inventory',
-    labelKey: 'spoolbuddy.nav.inventory',
-    fallback: 'Inventory',
-    icon: (
-      <svg className="w-6 h-6" fill="none" viewBox="0 0 24 24" stroke="currentColor">
-        <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M20 7l-8-4-8 4m16 0l-8 4m8-4v10l-8 4m0-10L4 7m8 4v10M4 7v10l8 4" />
-      </svg>
-    ),
-  },
   {
     to: '/spoolbuddy/settings',
     labelKey: 'spoolbuddy.nav.settings',