Phase 0 WP-0.1: Create .NET 10 solution structure with all 17 component projects

17 source projects (Commons + Host + 15 components) and 17 xUnit test projects.
SLNX format, net10.0, nullable enabled, warnings as errors. All components
reference Commons; Host references all components. Builds and tests clean.

src/ScadaLink.Host/Program.cs

@@ -0,0 +1,2 @@
+// See https://aka.ms/new-console-template for more information
+Console.WriteLine("Hello, World!");