feat: add missing translations across all locales

Add 692 translation keys across 21 locale files, covering admin actions, moderation, radio, catalog, and public UI strings.

src/messages/it.json

@@ -2350,14 +2350,24 @@
 					"typeStaff": "Solo staff",
 					"urgent": "Urgente",
 					"send": "Invia avviso",
-					"sending": "Invio…"
+					"sending": "Invio…",
+					"description": "Broadcasts via RCON <code>hotelalert</code> to online users."
 				},
 				"colId": "ID",
 				"colTitle": "Titolo",
 				"colSentBy": "Inviato da",
 				"colType": "Tipo",
 				"colDate": "Data",
-				"colActions": "Azioni"
+				"colActions": "Azioni",
+				"noAlerts": "No recent alerts",
+				"alertsShown": "Shown",
+				"critical": "Critical",
+				"warnings": "Warnings",
+				"unread": "Unread",
+				"markAllRead": "Mark all read",
+				"colWhen": "When",
+				"colSeverity": "Severity",
+				"colMessage": "Message"
 			},
 			"logs": {
 				"title": "Attività dello staff",