feat(logging): runtime Debug-build detection via DebuggableAttribute

tests/ClaudeDo.Worker.Tests/Logging/BuildConfigTests.cs

@@ -0,0 +1,19 @@
+using System.Diagnostics;
+using System.Reflection;
+using ClaudeDo.Logging;
+
+namespace ClaudeDo.Worker.Tests.Logging;
+
+public sealed class BuildConfigTests
+{
+    [Fact]
+    public void IsDebug_MatchesEntryAssemblyDebuggableAttribute()
+    {
+        var entry = Assembly.GetEntryAssembly();
+        var expected = entry?
+            .GetCustomAttribute<DebuggableAttribute>()
+            ?.IsJITOptimizerDisabled ?? false;
+
+        Assert.Equal(expected, BuildConfig.IsDebug);
+    }
+}