Fix audit findings for coverage, architecture checks, and XML docs

tests/CBDD.Tests/CompactionWalCoordinationTests.cs

@@ -6,6 +6,9 @@ namespace ZB.MOM.WW.CBDD.Tests;
 
 public class CompactionWalCoordinationTests
 {
+    /// <summary>
+    /// Verifies offline compaction checkpoints and leaves the WAL empty.
+    /// </summary>
     [Fact]
     public void OfflineCompact_ShouldCheckpointAndLeaveWalEmpty()
     {
@@ -42,6 +45,9 @@ public class CompactionWalCoordinationTests
         }
     }
 
+    /// <summary>
+    /// Verifies compaction after WAL recovery preserves durable data.
+    /// </summary>
     [Fact]
     public void Compact_AfterWalRecovery_ShouldKeepDataDurable()
     {