chore: update .gitignore and build.gradle.kts for local server testing

- Added entries to .gitignore for local Paper test server and API documentation.
- Included the run-paper plugin in build.gradle.kts for local server execution.
- Configured runServer task with Minecraft version 1.21.4 for testing.

src/main/java/com/loki/lochat/commands/base/AdminCommand.java

@@ -32,4 +32,4 @@ public abstract class AdminCommand extends BaseCommand {
      */
     protected abstract boolean executeAdminCommand(@NotNull CommandSender sender, @NotNull Command command, 
                                                  @NotNull String label, @NotNull String[] args);
-}
+}