feat(client): polished toolbar, live online count via SSE

- Redesign in-game client toolbar with refined glass styling and buttons
- Live online count + emulator status streamed over SSE multicast
- Who's-online tooltip throttled to reduce repeated requests
- Fix show button so it always returns the hidden toolbar
- Use theme CSS variables instead of hardcoded colors
- Add toolbar translations across all 25 locales

src/messages/it.json

@@ -3320,5 +3320,18 @@
 				}
 			}
 		}
+	},
+	"toolbar": {
+		"home": "Home",
+		"reload": "Ricarica",
+		"fullscreen": "Schermo intero",
+		"logout": "Esci",
+		"onlineUsers": "Utenti online",
+		"emulatorOnline": "Emulatore online",
+		"emulatorOffline": "Emulatore offline",
+		"dragToMove": "Trascina per spostare",
+		"hide": "Nascondi barra",
+		"fullscreenExit": "Esci dalla schermo intero",
+		"show": "Mostra barra"
 	}
 }