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/Configuration/AlarmsOptions.cs

@@ -0,0 +1,48 @@
+namespace ZB.MOM.WW.MxGateway.Server.Configuration;
+
+/// <summary>
+///     Configuration for the gateway's always-on central alarm monitor
+///     (<see cref="Alarms.GatewayAlarmMonitor"/>). When <see cref="Enabled"/>
+///     is true the gateway opens one gateway-owned worker session dedicated to
+///     alarms, caches the active-alarm set, and fans it out to every client
+///     through the <c>StreamAlarms</c> RPC — no client opens its own session
+///     to see alarms.
+/// </summary>
+/// <remarks>
+///     Defaults preserve current behaviour (alarm monitoring disabled).
+///     Operators opt in by setting <c>MxGateway:Alarms:Enabled = true</c> and
+///     supplying a canonical <c>\\&lt;machine&gt;\Galaxy!&lt;area&gt;</c>
+///     subscription expression. The literal "Galaxy" provider is correct
+///     regardless of the configured Galaxy database name (the wnwrap consumer
+///     does not accept the database name as the provider).
+/// </remarks>
+public sealed class AlarmsOptions
+{
+    /// <summary>Gate the gateway's always-on central alarm monitor. Default false.</summary>
+    public bool Enabled { get; init; }
+
+    /// <summary>
+    ///     AVEVA alarm-subscription expression the monitor subscribes on
+    ///     startup. When empty and <see cref="Enabled"/> is true, the gateway
+    ///     falls back to <c>\\$(MachineName)\Galaxy!$(DefaultArea)</c> if
+    ///     <see cref="DefaultArea"/> is set; otherwise the monitor faults with
+    ///     a configuration diagnostic.
+    /// </summary>
+    public string SubscriptionExpression { get; init; } = string.Empty;
+
+    /// <summary>
+    ///     Optional area name used to compose a default subscription when
+    ///     <see cref="SubscriptionExpression"/> is empty. Combined with
+    ///     <c>Environment.MachineName</c> as
+    ///     <c>\\&lt;MachineName&gt;\Galaxy!&lt;DefaultArea&gt;</c>.
+    /// </summary>
+    public string DefaultArea { get; init; } = string.Empty;
+
+    /// <summary>
+    ///     How often the monitor reconciles its in-process alarm cache against
+    ///     the worker's authoritative active-alarm snapshot, catching any
+    ///     transitions the live poll-and-diff feed missed. Default 30 seconds;
+    ///     the monitor floors it at 5 seconds.
+    /// </summary>
+    public int ReconcileIntervalSeconds { get; init; } = 30;
+}