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/Options/MbproxyOptionsBindingTests.cs

@@ -190,6 +190,28 @@ public sealed class MbproxyOptionsBindingTests
             string.Join("; ", result.Failures ?? []));
     }
 
+    // -------------------------------------------------------------------------
+    // Test 7 — AdminPushIntervalMs (SignalR dashboard push cadence)
+    // -------------------------------------------------------------------------
+    [Fact]
+    public void MbproxyOptionsBinding_AdminPushIntervalMs_DefaultsTo1000()
+    {
+        var options = BindOptions(new Dictionary<string, string?>());
+
+        options.AdminPushIntervalMs.ShouldBe(1000);
+    }
+
+    [Fact]
+    public void MbproxyOptionsBinding_AdminPushIntervalMs_BindsConfiguredValue()
+    {
+        var options = BindOptions(new Dictionary<string, string?>
+        {
+            ["Mbproxy:AdminPushIntervalMs"] = "250",
+        });
+
+        options.AdminPushIntervalMs.ShouldBe(250);
+    }
+
     /// <summary>
     /// Resolves an <c>install/</c> file by walking up from the test assembly directory.
     /// Works from both the Windows dev box and the Linux test box.