feat(scaffold): introduce 8 v2 component projects

Adds the empty project skeletons that subsequent v2 tasks fill in:

  src/Core/ZB.MOM.WW.OtOpcUa.Commons      (types, interfaces, message contracts)
  src/Core/ZB.MOM.WW.OtOpcUa.Cluster      (Akka.Hosting + cluster wiring)
  src/Server/ZB.MOM.WW.OtOpcUa.Security   (cookie+JWT auth, LDAP)
  src/Server/ZB.MOM.WW.OtOpcUa.ControlPlane (admin-role cluster singletons)
  src/Server/ZB.MOM.WW.OtOpcUa.Runtime    (per-node driver actors)
  src/Server/ZB.MOM.WW.OtOpcUa.OpcUaServer (OPC UA SDK application host)
  src/Server/ZB.MOM.WW.OtOpcUa.AdminUI    (Razor class library)
  src/Server/ZB.MOM.WW.OtOpcUa.Host       (single fused web binary)

Each project sets TreatWarningsAsErrors=true in its own csproj (per the
Directory.Build.props deviation note in the previous commit). NuGetAuditSuppress
entries cover transitive vulnerability advisories the new strictness surfaces:

  - GHSA-g94r-2vxg-569j (OpenTelemetry.Api 1.9.0 via Akka.Cluster.Hosting/Tools)
  - GHSA-h958-fxgg-g7w3 (Opc.Ua.Core 1.5.374.126 via OpcUaServer)
  - GHSA-37gx-xxp4-5rgx + GHSA-w3x6-4m5h-cxqf (legacy advisories already accepted)

OpcUaServer pins OPCFoundation.NetStandard.Opc.Ua.Configuration to 1.5.374.126
via VersionOverride to match Opc.Ua.Server's transitive Opc.Ua.Core (same
constraint as the legacy Server project).

Runtime does NOT project-reference any concrete Driver.* assemblies; drivers
load reflectively at runtime (Phase 6). Runtime gets the IDriver contract
through Core.Abstractions instead.

Host's Microsoft.Extensions.Hosting.WindowsServices is conditional on the
Windows OS so the project builds on macOS dev machines.

Build verification: dotnet build -> 438 warnings (all pre-existing xUnit1051
in legacy Server.Tests/Admin.Tests), 0 errors. Closes Task 9 (build green
smoke check, no separate commit).

src/Core/ZB.MOM.WW.OtOpcUa.Cluster/ZB.MOM.WW.OtOpcUa.Cluster.csproj

@@ -0,0 +1,28 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <RootNamespace>ZB.MOM.WW.OtOpcUa.Cluster</RootNamespace>
+        <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <PackageReference Include="Akka.Hosting"/>
+        <PackageReference Include="Akka.Cluster"/>
+        <PackageReference Include="Akka.Cluster.Hosting"/>
+        <PackageReference Include="Akka.Cluster.Tools"/>
+        <PackageReference Include="Akka.Remote.Hosting"/>
+        <PackageReference Include="Microsoft.Extensions.Hosting"/>
+        <PackageReference Include="Microsoft.Extensions.Options.ConfigurationExtensions"/>
+    </ItemGroup>
+
+    <ItemGroup>
+        <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Commons\ZB.MOM.WW.OtOpcUa.Commons.csproj"/>
+    </ItemGroup>
+
+    <ItemGroup>
+        <!-- OpenTelemetry.Api 1.9.0 reaches this project transitively from Akka.Cluster.Hosting.
+             Bump arrives when Akka updates its OTel dependency; tracked separately. -->
+        <NuGetAuditSuppress Include="https://github.com/advisories/GHSA-g94r-2vxg-569j"/>
+    </ItemGroup>
+
+</Project>

src/Core/ZB.MOM.WW.OtOpcUa.Commons/ZB.MOM.WW.OtOpcUa.Commons.csproj

@@ -0,0 +1,12 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <RootNamespace>ZB.MOM.WW.OtOpcUa.Commons</RootNamespace>
+        <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
+    </PropertyGroup>
+
+    <ItemGroup>
+        <PackageReference Include="Akka"/>
+    </ItemGroup>
+
+</Project>