chore: housekeeping — linter & formatter setup

Add .prettierrc.json, .markdownlint.json, .yamllint.yaml, .gitattributes
Run CSharpier, Prettier and markdownlint across the entire codebase.
No logic changes — formatting, using order and line endings only.

HellionChat/Util/WrapperUtil.cs

@@ -1,5 +1,5 @@
-using HellionChat.Resources;
-using Dalamud.Interface.ImGuiNotification;
+using Dalamud.Interface.ImGuiNotification;
+using HellionChat.Resources;
 
 namespace HellionChat.Util;
 
@@ -7,7 +7,14 @@ public static class WrapperUtil
 {
     public static void AddNotification(string content, NotificationType type, bool minimized = true)
     {
-        Plugin.Notification.AddNotification(new Notification { Content = content, Type = type, Minimized = minimized });
+        Plugin.Notification.AddNotification(
+            new Notification
+            {
+                Content = content,
+                Type = type,
+                Minimized = minimized,
+            }
+        );
     }
 
     public static void TryOpenUri(Uri uri)
@@ -23,4 +30,4 @@ public static class WrapperUtil
             AddNotification(Language.Context_OpenInBrowserError, NotificationType.Error);
         }
     }
-}
+}