fix: switch to NuGet package reference for CMS Protobuf (Docker build fix)

- Changed from ProjectReference to PackageReference (v0.0.178)
- Removed COPY libs/ from Dockerfile (no longer needed)
- Docker build context (src/) cannot resolve ../../../CMS path
- NuGet package restored from Nexus registry

src/BackOffice/BackOffice.csproj

@@ -136,9 +136,9 @@
     <!-- This enables direct communication with CMS (no BFF needed)   -->
     <!-- ============================================================ -->
     
-    <!-- Direct reference to CMS Protobuf project -->
+    <!-- CMS Protobuf NuGet package (used for both local dev and Docker builds) -->
     <ItemGroup>
-        <ProjectReference Include="../../../CMS/src/CMSMicroservice.Protobuf/CMSMicroservice.Protobuf.csproj" />
+        <PackageReference Include="Foursat.CMSMicroservice.Protobuf" Version="0.0.178" />
     </ItemGroup>
     
     <!-- ============================================================ -->

src/BackOffice/Dockerfile

@@ -5,9 +5,6 @@ WORKDIR /src
 COPY ["BackOffice/NuGet.config", "NuGet.config"]
 COPY ["BackOffice/BackOffice.csproj", "BackOffice/"]
 
-# Copy libs folder with pre-built DLLs (built by build-deps.sh)
-COPY ["libs/", "libs/"]
-
 # Restore dependencies
 RUN dotnet restore "BackOffice/BackOffice.csproj" --configfile NuGet.config