Add DorkNet.Contracts reference to monolith Server build

DorkNet.Server uses DorkNetRouteOwnership from DorkNet.Contracts but the
project never referenced it and the Dockerfile never copied it, so the
monolith image failed to compile (CS0234). Add the project reference and
copy the project into the build stage.

Dockerfile

@@ -53,12 +53,14 @@ WORKDIR /src
 # DorkNet.Models project ref, so its csproj needs to be present too.
 COPY DorkNet.Server/DorkNet.Server.csproj DorkNet.Server/
 COPY DorkNet.Models/DorkNet.Models.csproj DorkNet.Models/
+COPY DorkNet.Contracts/DorkNet.Contracts.csproj DorkNet.Contracts/
 RUN dotnet restore DorkNet.Server/DorkNet.Server.csproj
 
 # Now copy the rest of the .NET source, then drop the prebuilt admin
 # SPA into wwwroot/admin so the publish step ships it as static content.
 COPY DorkNet.Server/ DorkNet.Server/
 COPY DorkNet.Models/ DorkNet.Models/
+COPY DorkNet.Contracts/ DorkNet.Contracts/
 COPY --from=admin-ui /wwwroot/admin/ DorkNet.Server/wwwroot/admin/
 COPY --from=site      /wwwroot/site/  DorkNet.Server/wwwroot/site/
 

DorkNet.Server/DorkNet.Server.csproj

@@ -73,6 +73,7 @@
 
   <ItemGroup>
     <ProjectReference Include="..\DorkNet.Models\DorkNet.Models.csproj" />
+    <ProjectReference Include="..\DorkNet.Contracts\DorkNet.Contracts.csproj" />
   </ItemGroup>
 
   <!-- Service-slice containers reference DorkNet.Server for shared controllers