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/Sheets.cs

@@ -32,12 +32,12 @@ public static class Sheets
     }
 
     public static bool IsInForay() =>
-        TerritorySheet.TryGetRow(Plugin.ClientState.TerritoryType, out var row) &&
-        row.TerritoryIntendedUse.RowId is 41 or 61;
+        TerritorySheet.TryGetRow(Plugin.ClientState.TerritoryType, out var row)
+        && row.TerritoryIntendedUse.RowId is 41 or 61;
 
     public static IEnumerable<World> WorldsOnDatacenter(IPlayerCharacter character)
     {
         var dcRow = character.HomeWorld.Value.DataCenter.RowId;
         return WorldSheet.Where(world => world.IsPublic && world.DataCenter.RowId == dcRow);
     }
-}
+}