feat(settings): group commands by category in system tab

bot/lib/loaders/CommandLoader.ts

@@ -72,7 +72,7 @@ export class CommandLoader {
                     command.category = category;
 
                     // Track all known commands regardless of enabled status
-                    this.client.knownCommands.add(command.data.name);
+                    this.client.knownCommands.set(command.data.name, category);
 
                     const isEnabled = config.commands[command.data.name] !== false;