refactor: rename namespace to FiscalFlow and upgrade to .NET 10

- Rename InvoiceMaster.* to FiscalFlow.* namespace
- Upgrade from .NET 8 to .NET 10
- Update all NuGet packages to latest versions
- Update C# language version to 14.0

backend/tests/InvoiceMaster.UnitTests/obj/Debug/net8.0/InvoiceMaster.UnitTests.AssemblyInfo.cs

@@ -13,7 +13,7 @@ using System.Reflection;
 [assembly: System.Reflection.AssemblyCompanyAttribute("InvoiceMaster.UnitTests")]
 [assembly: System.Reflection.AssemblyConfigurationAttribute("Debug")]
 [assembly: System.Reflection.AssemblyFileVersionAttribute("1.0.0.0")]
-[assembly: System.Reflection.AssemblyInformationalVersionAttribute("1.0.0")]
+[assembly: System.Reflection.AssemblyInformationalVersionAttribute("1.0.0+05ea67144f6a97e372ca4293ce2393e15a3f6bb7")]
 [assembly: System.Reflection.AssemblyProductAttribute("InvoiceMaster.UnitTests")]
 [assembly: System.Reflection.AssemblyTitleAttribute("InvoiceMaster.UnitTests")]
 [assembly: System.Reflection.AssemblyVersionAttribute("1.0.0.0")]

backend/tests/InvoiceMaster.UnitTests/obj/Debug/net8.0/InvoiceMaster.UnitTests.AssemblyInfoInputs.cache

@@ -1 +1 @@
-1223dddf7216ddab048329fa70034587d349b759b5b033e38e6cd2d4edbd4866
+c077d4836482878dfcee69c0e412646849a04e73aee8bbed7559e6bb4a662308