docs: backfill XML documentation across 756 files

Adds <summary>, <param>, <typeparam>, and <inheritdoc/> tags to public
members surfaced by commentchecker — resolves 5,847 of 5,869 issues
(99.6%) across three /fixdocs passes.

tests/Core/ZB.MOM.WW.OtOpcUa.Configuration.Tests/SchemaComplianceFixture.cs

@@ -16,9 +16,12 @@ public sealed class SchemaComplianceFixture : IDisposable
     private const string DefaultServer = "10.100.0.35,14330";
     private const string DefaultSaPassword = "OtOpcUaDev_2026!";
 
+    /// <summary>Gets the name of the test database.</summary>
     public string DatabaseName { get; }
+    /// <summary>Gets the connection string for the test database.</summary>
     public string ConnectionString { get; }
 
+    /// <summary>Initializes a new instance of the SchemaComplianceFixture class.</summary>
     public SchemaComplianceFixture()
     {
         var server = Environment.GetEnvironmentVariable("OTOPCUA_CONFIG_TEST_SERVER") ?? DefaultServer;
@@ -36,6 +39,8 @@ public sealed class SchemaComplianceFixture : IDisposable
         ctx.Database.Migrate();
     }
 
+    /// <summary>Opens a new SQL connection to the test database.</summary>
+    /// <returns>An open SQL connection.</returns>
     public SqlConnection OpenConnection()
     {
         var conn = new SqlConnection(ConnectionString);
@@ -43,6 +48,7 @@ public sealed class SchemaComplianceFixture : IDisposable
         return conn;
     }
 
+    /// <summary>Disposes the fixture and drops the test database.</summary>
     public void Dispose()
     {
         var masterConnection =