Refactor project files for improved readability and structure

- Cleaned up whitespace in Directory.Build.props and Directory.Packages.props for consistency.
- Reformatted project file references in PnvPanel.Api.csproj for better clarity.
- Enhanced code readability in various endpoint files by adjusting line breaks and indentation.
- Standardized method signatures and improved formatting in ResultExtensions and multiple endpoint classes for better maintainability.

backend/src/PnvPanel.Infrastructure/Persistence/Migrations/20260701161345_InitialCreate.cs

@@ -8,15 +8,9 @@ namespace PnvPanel.Infrastructure.Persistence.Migrations
     public partial class InitialCreate : Migration
     {
         /// <inheritdoc />
-        protected override void Up(MigrationBuilder migrationBuilder)
-        {
-
-        }
+        protected override void Up(MigrationBuilder migrationBuilder) { }
 
         /// <inheritdoc />
-        protected override void Down(MigrationBuilder migrationBuilder)
-        {
-
-        }
+        protected override void Down(MigrationBuilder migrationBuilder) { }
     }
 }