Wire up decode puzzle chain and lock terminal on file removal

Connects the previously-disconnected /decode command to per-player
messages: player 1 unlocks sudo for everyone, player 2 unlocks a scan
command that reveals which files the AI virus has locked, player 3
learns those files should be removed.

Also adds a retaliation mechanic: successfully removing a file locks
the player's terminal. The AI virus locks it out in red immediately;
the mainframe reveals a 12-character recovery code in green after 30
seconds, which can be submitted via /unlock to restore access early,
otherwise the terminal auto-recovers after 45 seconds.

src/Game/Enum/DecodeMessage.php

@@ -4,7 +4,7 @@ namespace App\Game\Enum;
 
 enum DecodeMessage: string
 {
-    case TEST = 'This is a test decoding message.';
-    case SECRET = 'The secret code is 42.';
-    case WELCOME = 'Welcome to the system, agent.';
+    case PLAYER_1 = 'Sudo is now available';
+    case PLAYER_2 = 'AI virus protects its own files by replacing them';
+    case PLAYER_3 = 'The locked up bash files should be removed to lock it up';
 }