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/GameFunctions/Context.cs

@@ -1,7 +1,7 @@
-using HellionChat.Util;
 using FFXIVClientStructs.FFXIV.Client.UI.Agent;
 using FFXIVClientStructs.FFXIV.Client.UI.Info;
 using FFXIVClientStructs.FFXIV.Client.UI.Misc;
+using HellionChat.Util;
 
 namespace HellionChat.GameFunctions;
 
@@ -10,7 +10,9 @@ internal sealed unsafe class Context
     internal static void InviteToNoviceNetwork(string name, ushort world)
     {
         // can specify content id if we have it, but there's no need
-        InfoProxyNoviceNetwork.Instance()->InviteToNoviceNetwork(0, 0, world, name.ToTerminatedBytes());
+        InfoProxyNoviceNetwork
+            .Instance()
+            ->InviteToNoviceNetwork(0, 0, world, name.ToTerminatedBytes());
     }
 
     internal static void TryOn(uint itemId, byte stainId)