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/tests/PnvPanel.IntegrationTests/PnvPanel.IntegrationTests.csproj

@@ -1,5 +1,4 @@
 <Project Sdk="Microsoft.NET.Sdk">
-
   <PropertyGroup>
     <TargetFramework>net10.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
@@ -24,5 +23,4 @@
   <ItemGroup>
     <ProjectReference Include="..\..\src\PnvPanel.Api\PnvPanel.Api.csproj" />
   </ItemGroup>
-
 </Project>