zio fork 1.8.2b-zio5: staff chat shows rank

@ in team chat and css_asay read ">[STAFF][RANK] name: message", and @ in all chat and a
player's css_say read ">[RANK] name: message", with the rank from the sender's highest #rank/...
group (O, SA, A, TA, M, TM, H). Staff in no rank group get ">[STAFF] name" and "> name". A
non-staff player's @ team chat reads ">[PLAYER] name: message". Console's messages are unchanged.
The lines are new en.json keys: sa_staffchat_template, sa_staffsay_template, their _norank
variants and sa_staffchat_template_player.

CS2-SimpleAdmin/Helper.cs

@@ -144,6 +144,30 @@ internal static class Helper
         return string.Join(" ", parts);
     }
 
+    // zio: staff rank groups, highest first, and their chat abbreviations.
+    private static readonly (string Group, string Tag)[] StaffRanks =
+    [
+        ("#rank/owner", "O"),
+        ("#rank/senioradmin", "SA"),
+        ("#rank/admin", "A"),
+        ("#rank/trialadmin", "TA"),
+        ("#rank/mod", "M"),
+        ("#rank/trialmod", "TM"),
+        ("#rank/helper", "H"),
+    ];
+
+    // zio: the player's highest staff rank abbreviation, or null if they're in no rank group.
+    internal static string? GetStaffRankTag(CCSPlayerController player)
+    {
+        var groups = AdminManager.GetPlayerAdminData(new SteamID(player.SteamID))?.Groups;
+        if (groups == null) return null;
+        foreach (var (group, tag) in StaffRanks)
+        {
+            if (groups.Contains(group)) return tag;
+        }
+        return null;
+    }
+
     public static void KickPlayer(int userId, NetworkDisconnectionReason reason = NetworkDisconnectionReason.NETWORK_DISCONNECT_KICKED, int delay = 0)
     {
         var player = Utilities.GetPlayerFromUserid(userId);