feat(secrets): add ZB.MOM.WW.Secrets refs + pre-host ${secret:} expander (Tasks 1-2)

Adopt the ZB.MOM.WW.Secrets library (0.1.2, Gitea feed) into OtOpcUa under CPM:
- Directory.Packages.props + NuGet.config source mapping for the three packages
- Host/AdminUI/Driver.Galaxy.Contracts/Driver.OpcUaClient package references
- Layer-A pre-host ${secret:} config expander in Host/Program.cs, placed after all
  config providers assemble and before the first config read (mechanism only,
  behavior-neutral no-op until Task 4 introduces tokens)
- Secrets section in appsettings.json (env-var KEK, SQLite store, 30s cache TTL)

Mechanism mirrors the proven HistorianGateway adoption. KEK never committed.

Directory.Packages.props

@@ -132,6 +132,9 @@
     <PackageVersion Include="ZB.MOM.WW.Auth.Abstractions" Version="0.1.1" />
     <PackageVersion Include="ZB.MOM.WW.Auth.Ldap" Version="0.1.1" />
     <PackageVersion Include="ZB.MOM.WW.Auth.AspNetCore" Version="0.1.1" />
+    <PackageVersion Include="ZB.MOM.WW.Secrets" Version="0.1.2" />
+    <PackageVersion Include="ZB.MOM.WW.Secrets.Abstractions" Version="0.1.2" />
+    <PackageVersion Include="ZB.MOM.WW.Secrets.Ui" Version="0.1.2" />
     <PackageVersion Include="ZB.MOM.WW.Audit" Version="0.1.0" />
     <PackageVersion Include="ZB.MOM.WW.Theme" Version="0.3.1" />
     <PackageVersion Include="ZB.MOM.WW.HistorianGateway.Client" Version="0.3.0" />

NuGet.config

@@ -25,6 +25,8 @@
       <package pattern="ZB.MOM.WW.Theme" />
       <package pattern="ZB.MOM.WW.HistorianGateway.Contracts" />
       <package pattern="ZB.MOM.WW.HistorianGateway.Client" />
+      <package pattern="ZB.MOM.WW.Secrets" />
+      <package pattern="ZB.MOM.WW.Secrets.*" />
     </packageSource>
   </packageSourceMapping>
 </configuration>

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Contracts/ZB.MOM.WW.OtOpcUa.Driver.Galaxy.Contracts.csproj

@@ -13,5 +13,6 @@
         <ProjectReference Include="..\..\Core\ZB.MOM.WW.OtOpcUa.Core.Abstractions\ZB.MOM.WW.OtOpcUa.Core.Abstractions.csproj" />
         <!-- Logging abstraction needed by GalaxySecretRef.ResolveApiKey's optional warning logger. -->
         <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" />
+        <PackageReference Include="ZB.MOM.WW.Secrets.Abstractions" />
     </ItemGroup>
 </Project>

src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient/ZB.MOM.WW.OtOpcUa.Driver.OpcUaClient.csproj

@@ -21,6 +21,7 @@
     <ItemGroup>
         <PackageReference Include="OPCFoundation.NetStandard.Opc.Ua.Client"/>
         <PackageReference Include="OPCFoundation.NetStandard.Opc.Ua.Configuration"/>
+        <PackageReference Include="ZB.MOM.WW.Secrets.Abstractions"/>
     </ItemGroup>
 
     <ItemGroup>

src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/ZB.MOM.WW.OtOpcUa.AdminUI.csproj

@@ -10,6 +10,7 @@
         <FrameworkReference Include="Microsoft.AspNetCore.App"/>
         <PackageReference Include="Microsoft.AspNetCore.SignalR.Client"/>
         <PackageReference Include="ZB.MOM.WW.Theme"/>
+        <PackageReference Include="ZB.MOM.WW.Secrets.Ui"/>
     </ItemGroup>
 
     <ItemGroup>

src/Server/ZB.MOM.WW.OtOpcUa.Host/Program.cs

@@ -37,6 +37,11 @@ using ZB.MOM.WW.OtOpcUa.Security.Ldap;
 using ZB.MOM.WW.Configuration;
 using ZB.MOM.WW.Telemetry.Serilog;
 using ZB.MOM.WW.OtOpcUa.AdminUI.Api;
+using Microsoft.Extensions.DependencyInjection;
+using ZB.MOM.WW.Secrets.Abstractions;
+using ZB.MOM.WW.Secrets.Configuration;
+using ZB.MOM.WW.Secrets.DependencyInjection;
+using ZB.MOM.WW.Secrets.Sqlite;
 
 // Roles drive the entire conditional wiring below — see ZB.MOM.WW.OtOpcUa.Cluster.RoleParser.
 var roles = RoleParser.Parse(Environment.GetEnvironmentVariable("OTOPCUA_ROLES"));
@@ -72,6 +77,27 @@ if (roleSuffix is not null)
     builder.Configuration.AddCommandLine(args);
 }
 
+// Pre-host ${secret:} expansion: rewrites ${secret:name} tokens in the assembled configuration
+// BEFORE the host is built, so every downstream binder/validator sees resolved plaintext.
+// Placement matters: this runs AFTER all config providers are assembled (base appsettings, the
+// role overlay, and the env-vars + command-line re-append above) but BEFORE anything READS a
+// config value (AddZbSerilog's ReadFrom.Configuration, AddOtOpcUaConfigDb, and the first
+// ValidateOnStart bind all follow). With no ${secret:} tokens present this is a no-op pass;
+// it also migrates the secrets SQLite store on startup.
+// ASP0000: DELIBERATE throwaway container — expansion must run before builder.Build(), so it
+// cannot use the app's DI. Fully disposed here; shares no singletons with the host container.
+#pragma warning disable ASP0000
+await using (var secretsProvider = new ServiceCollection()
+    .AddZbSecrets(builder.Configuration, "Secrets")
+    .BuildServiceProvider())
+#pragma warning restore ASP0000
+{
+    await secretsProvider.GetRequiredService<SqliteSecretsStoreMigrator>().MigrateAsync(default);
+    var resolver = secretsProvider.GetRequiredService<ISecretResolver>();
+    await new SecretReferenceExpander(resolver)
+        .ExpandConfigurationAsync((IConfigurationRoot)builder.Configuration, default);
+}
+
 // Anchor the process working directory to the install directory (AppContext.BaseDirectory) so every
 // relative runtime path resolves under the install dir rather than the service's startup CWD. A Windows
 // service starts with CWD=C:\Windows\System32, which otherwise scattered the Serilog rolling-file sink

src/Server/ZB.MOM.WW.OtOpcUa.Host/ZB.MOM.WW.OtOpcUa.Host.csproj

@@ -33,6 +33,8 @@
         <PackageReference Include="ZB.MOM.WW.Telemetry" />
         <PackageReference Include="ZB.MOM.WW.Telemetry.Serilog" />
         <PackageReference Include="ZB.MOM.WW.Configuration" />
+        <PackageReference Include="ZB.MOM.WW.Secrets" />
+        <PackageReference Include="ZB.MOM.WW.Secrets.Abstractions" />
     </ItemGroup>
 
     <ItemGroup>

src/Server/ZB.MOM.WW.OtOpcUa.Host/appsettings.json

@@ -11,6 +11,15 @@
       "DisableLogin": false
     }
   },
+  "Secrets": {
+    "SqlitePath": "otopcua-secrets.db",
+    "MasterKey": {
+      "Source": "Environment",
+      "EnvVarName": "ZB_SECRETS_MASTER_KEY"
+    },
+    "RunMigrationsOnStartup": true,
+    "ResolveCacheTtl": "00:00:30"
+  },
   "ServerHistorian": {
     "_comment": "Server-side HistoryRead backend (the ZB.MOM.WW.HistorianGateway gRPC client). Disabled => NullHistorianDataSource (historized nodes return GoodNoData). The gateway must run RuntimeDb:EventReadsEnabled=true for alarm-history ReadEvents, and the API key must carry historian:read + historian:write + historian:tags:write scopes.",
     "Enabled": false,