fix(client/dotnet): restore warnings-as-errors floor; license metadata; LazyBrowseNode publication (Client.Dotnet-022..025)

clients/dotnet/Directory.Build.props

@@ -1,4 +1,17 @@
 <Project>
+  <PropertyGroup>
+    <!-- Build-quality enforcement floor, mirroring src/Directory.Build.props so the
+         .NET client tree is held to the same baseline CLAUDE.md mandates (warnings as
+         errors, code-style enforced at build, latest analyzers, deterministic builds). -->
+    <LangVersion>latest</LangVersion>
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
+    <AnalysisLevel>latest</AnalysisLevel>
+    <EnforceCodeStyleInBuild>true</EnforceCodeStyleInBuild>
+    <Deterministic>true</Deterministic>
+  </PropertyGroup>
+
   <PropertyGroup>
     <!-- Shared package metadata for clients/dotnet/. Individual projects opt in via <IsPackable>true</IsPackable>. -->
     <Authors>Joseph Doherty</Authors>
@@ -10,11 +23,15 @@
     <PackageProjectUrl>https://gitea.dohertylan.com/dohertj2/mxaccessgw</PackageProjectUrl>
     <PackageTags>mxaccess;mxgateway;grpc;client;archestra</PackageTags>
     <PackageRequireLicenseAcceptance>false</PackageRequireLicenseAcceptance>
+    <!-- Proprietary/internal package, consistent with the Rust ("Proprietary") and
+         Python ("Proprietary") client license declarations. A LicenseRef SPDX expression
+         is rejected by the current NuGet toolset (NU5124), so the proprietary terms ship
+         as a packaged license file instead. -->
+    <PackageLicenseFile>LICENSE.txt</PackageLicenseFile>
     <!-- Versioning: bump per release. Symbols ship as snupkg. -->
     <Version>0.1.0</Version>
     <IncludeSymbols>true</IncludeSymbols>
     <SymbolPackageFormat>snupkg</SymbolPackageFormat>
-    <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <!-- Default: do NOT pack. Each project opts in. -->
     <IsPackable>false</IsPackable>
   </PropertyGroup>