rename: prefix gateway projects/namespaces with ZB.MOM.WW + sln→slnx

Apply the ZB.MOM.WW. prefix to all gateway-side projects, folders,
.csproj/.sln contents, C# namespaces, using directives, generated proto
C# (csharp_namespace + checked-in generated files), InternalsVisibleTo
attributes, project-name string literals (LoadProject, .sln lookups,
worker exe paths, staticwebassets manifest), and the install/script/doc
references that point at any of the above. Migrate the solution from
.sln to .slnx via `dotnet sln migrate` and delete the old file.

External-runtime identifiers are intentionally NOT prefixed so external
configuration keeps working:
- GatewayMetrics.cs MeterName ("MxGateway.Server")
- DashboardAuthenticationDefaults Scheme/Policy ("MxGateway.Dashboard")
- GatewayRequestLoggingMiddleware logger category ("MxGateway.Request")
- StaRuntime thread name ("MxGateway.Worker.STA")
- appsettings.json root section "MxGateway" + env-var prefix
  MxGateway__... and secret-name MxGateway:ApiKeyPepper
- C:\ProgramData\MxGateway\ data dir paths

Also fixes two tests that were not rename-related but became visible
while validating the rename:

- WorkerLiveMxAccessSmokeTests.ShutDownAsync: cancellation that the
  gateway service correctly maps to RpcException(Cancelled) per gRPC
  convention was being misclassified as a stream fault. Added a sibling
  catch on RpcException with StatusCode.Cancelled.

- IntegrationTestEnvironment.ResolveRepositoryRoot: extracted IsRepositoryRoot
  and made it accept either a .git marker OR a .sln/.slnx next to src/
  so the worker-exe walker works in non-git working copies.

clients/proto/proto-inputs.json's protoRoot updated to point at
src/ZB.MOM.WW.MxGateway.Contracts/Protos.

Verified by `dotnet build` and a full `dotnet test` of the .slnx with
MXGATEWAY_RUN_LIVE_{MXACCESS,LDAP,GALAXY}_TESTS=1:
  Tests: 472/472 pass
  Worker.Tests: 280/280 pass (4 dev-rig [Fact(Skip=...)] skipped)
  IntegrationTests: 18/18 pass

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/ZB.MOM.WW.MxGateway.Server/Program.cs

@@ -0,0 +1,43 @@
+using ZB.MOM.WW.MxGateway.Server;
+using ZB.MOM.WW.MxGateway.Server.Configuration;
+using ZB.MOM.WW.MxGateway.Server.Security.Authentication;
+
+ApiKeyAdminParseResult apiKeyAdminCommand = ApiKeyAdminCommandLineParser.Parse(args);
+if (apiKeyAdminCommand.IsApiKeyCommand)
+{
+    if (apiKeyAdminCommand.Command is null)
+    {
+        await Console.Error.WriteLineAsync(apiKeyAdminCommand.Error);
+        return 2;
+    }
+
+    WebApplicationBuilder builder = GatewayApplication.CreateBuilder([]);
+    ApplyApiKeyAdminOverrides(builder.Configuration, apiKeyAdminCommand.Command);
+    await using WebApplication cliApp = builder.Build();
+    await using AsyncServiceScope scope = cliApp.Services.CreateAsyncScope();
+
+    ApiKeyAdminCliRunner runner = scope.ServiceProvider.GetRequiredService<ApiKeyAdminCliRunner>();
+
+    return await runner.RunAsync(apiKeyAdminCommand.Command, Console.Out, CancellationToken.None);
+}
+
+WebApplication app = GatewayApplication.Build(args);
+
+app.Run();
+
+return 0;
+
+static void ApplyApiKeyAdminOverrides(IConfiguration configuration, ApiKeyAdminCommand command)
+{
+    if (!string.IsNullOrWhiteSpace(command.SqlitePath))
+    {
+        configuration[$"{GatewayOptions.SectionName}:Authentication:SqlitePath"] = command.SqlitePath;
+    }
+
+    if (!string.IsNullOrWhiteSpace(command.Pepper))
+    {
+        configuration["MxGateway:ApiKeyPepper"] = command.Pepper;
+    }
+}
+
+public partial class Program;