mbproxy: replace status page with a live SignalR web dashboard

The single auto-refreshing zero-JS status page gave operators a 25-column
wall and no way to drill into one connection. This adds a Bootstrap fleet
dashboard (filterable/sortable KPI table) and a per-PLC detail page with a
real-time debug view of raw PLC-side BCD vs. decoded client-side values,
streamed live over a SignalR feed. The debug view is fed by an on-demand
per-tag value capture, armed only while a detail page is open. All assets
(Bootstrap, SignalR client, fonts) are embedded so the UI works unchanged
on firewalled networks; GET /status.json is untouched for scrapers.

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

mbproxy/tests/Mbproxy.Tests/Configuration/ConfigReconcilerTests.cs

@@ -73,7 +73,8 @@ public sealed class ConfigReconcilerTests : IAsyncDisposable
         return new ConfigReconciler(
             monitor,
             NullLoggerFactory.Instance,
-            counters ?? new ServiceCounters());
+            counters ?? new ServiceCounters(),
+            new Mbproxy.Proxy.TagCaptureRegistry());
     }
 
     // The reconciler and supervisors tracked for cleanup.