Apply technical-light design system to the gateway dashboard

Restyles the Blazor dashboard onto a portable token-based theme so it
reads like an instrument panel: warm-paper background, hairline-ruled
panels, IBM Plex type, monospace tabular numerics, and status carried by
colour chips. Vendors theme.css + IBM Plex fonts, rewrites dashboard.css
as a thin token-driven view layer, and swaps the Bootstrap navbar and
status badges for the design-system app bar and chips.

Also includes pending API-key management, Galaxy hierarchy projection,
and constraint-enforcement work with their tests.

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

src/MxGateway.IntegrationTests/LiveLdapFactAttribute.cs

@@ -0,0 +1,20 @@
+namespace MxGateway.IntegrationTests;
+
+public sealed class LiveLdapFactAttribute : FactAttribute
+{
+    public const string EnableVariableName = "MXGATEWAY_RUN_LIVE_LDAP_TESTS";
+
+    public LiveLdapFactAttribute()
+    {
+        if (!Enabled)
+        {
+            Skip = $"Set {EnableVariableName}=1 to run live LDAP tests.";
+        }
+    }
+
+    public static bool Enabled =>
+        string.Equals(
+            Environment.GetEnvironmentVariable(EnableVariableName),
+            "1",
+            StringComparison.Ordinal);
+}