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/Dashboard/Components/Layout/DashboardLayout.razor

@@ -0,0 +1,50 @@
+@inherits LayoutComponentBase
+@inject IOptions<GatewayOptions> GatewayOptions
+
+<div class="dashboard-shell">
+    <header class="app-bar">
+        <a class="brand" href=""><span class="mark">&#9646;</span> MXAccess Gateway</a>
+        <nav class="app-nav">
+            <NavLink href="" Match="NavLinkMatch.All">Overview</NavLink>
+            <NavLink href="sessions">Sessions</NavLink>
+            <NavLink href="workers">Workers</NavLink>
+            <NavLink href="events">Events</NavLink>
+            <NavLink href="galaxy">Galaxy</NavLink>
+            <NavLink href="browse">Browse</NavLink>
+            <NavLink href="alarms">Alarms</NavLink>
+            <NavLink href="apikeys">API Keys</NavLink>
+            <NavLink href="settings">Settings</NavLink>
+        </nav>
+        <span class="spacer"></span>
+        <AuthorizeView>
+            <Authorized Context="authState">
+                <div class="app-user">
+                    <span class="meta">@authState.User.Identity?.Name</span>
+                    <form method="post" action="@DashboardPath("/logout")">
+                        <AntiforgeryToken />
+                        <button class="btn btn-outline-secondary btn-sm" type="submit">Sign out</button>
+                    </form>
+                </div>
+            </Authorized>
+            <NotAuthorized>
+                <a class="btn btn-outline-secondary btn-sm" href="@DashboardPath("/login")">Sign in</a>
+            </NotAuthorized>
+        </AuthorizeView>
+    </header>
+    <main class="page">
+        @Body
+    </main>
+</div>
+
+@code {
+    private string DashboardPath(string relativePath)
+    {
+        string pathBase = GatewayOptions.Value.Dashboard.PathBase.TrimEnd('/');
+        if (string.IsNullOrWhiteSpace(pathBase))
+        {
+            pathBase = "/dashboard";
+        }
+
+        return $"{pathBase}{relativePath}";
+    }
+}