feat: auto-generate CalVer version from build date

Replace hardcoded AssemblyVersion/AssemblyFileVersion with a CalVer
scheme (YYYY.M.D.HHmm) generated at build time via an MSBuild target
that writes a CalVer.cs file into obj/ before compilation.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

MosswartMassacre/MosswartMassacre.csproj

@@ -388,4 +388,16 @@
     <Error Condition="!Exists('..\packages\Costura.Fody.5.7.0\build\Costura.Fody.targets')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\Costura.Fody.5.7.0\build\Costura.Fody.targets'))" />
   </Target>
   <Import Project="..\packages\Costura.Fody.5.7.0\build\Costura.Fody.targets" Condition="Exists('..\packages\Costura.Fody.5.7.0\build\Costura.Fody.targets')" />
+  <!-- Auto-generate CalVer version: YYYY.M.D.HHmm -->
+  <Target Name="SetCalVer" BeforeTargets="CoreCompile">
+    <PropertyGroup>
+      <CalVerVersion>$([System.DateTime]::UtcNow.ToString("yyyy.M.d.HHmm"))</CalVerVersion>
+      <CalVerFile>$(IntermediateOutputPath)CalVer.cs</CalVerFile>
+    </PropertyGroup>
+    <WriteLinesToFile File="$(CalVerFile)" Overwrite="true"
+      Lines="using System.Reflection%3B;[assembly: AssemblyVersion(&quot;$(CalVerVersion)&quot;)];[assembly: AssemblyFileVersion(&quot;$(CalVerVersion)&quot;)]" />
+    <ItemGroup>
+      <Compile Include="$(CalVerFile)" />
+    </ItemGroup>
+  </Target>
 </Project>

MosswartMassacre/Properties/AssemblyInfo.cs

@@ -21,10 +21,4 @@ using System.Runtime.InteropServices;
 // The following GUID is for the ID of the typelib if this project is exposed to COM
 [assembly: Guid("9b6a07e1-ae78-47f4-b09c-174f6a27d7a3")]
 
-// Version information for an assembly consists of the following four values:
+// Version is auto-generated at build time (CalVer: YYYY.M.D.HHmm)
-//      Major Version
-//      Minor Version 
-//      Build Number
-//      Revision
-[assembly: AssemblyVersion("4.0.0.2")]
-[assembly: AssemblyFileVersion("4.0.0.2")]