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/Server/ZB.MOM.WW.OtOpcUa.Runtime.Tests/ServiceCollectionExtensionsTests.cs

@@ -17,6 +17,7 @@ namespace ZB.MOM.WW.OtOpcUa.Runtime.Tests;
 /// </summary>
 public sealed class ServiceCollectionExtensionsTests
 {
+    /// <summary>Verifies that WithOtOpcUaRuntimeActors spawns driver host and DB health probe actors.</summary>
     [Fact]
     public async Task WithOtOpcUaRuntimeActors_spawns_driver_host_and_db_health_probe()
     {
@@ -67,8 +68,10 @@ public sealed class ServiceCollectionExtensionsTests
         }
     }
 
+    /// <summary>In-memory database factory for testing.</summary>
     private sealed class InMemoryConfigDbFactory(string dbName) : IDbContextFactory<OtOpcUaConfigDbContext>
     {
+        /// <summary>Creates a new in-memory database context.</summary>
         public OtOpcUaConfigDbContext CreateDbContext()
         {
             var opts = new DbContextOptionsBuilder<OtOpcUaConfigDbContext>()
@@ -78,13 +81,25 @@ public sealed class ServiceCollectionExtensionsTests
         }
     }
 
+    /// <summary>Fake cluster role information for testing.</summary>
     private sealed class FakeClusterRoleInfo : IClusterRoleInfo
     {
+        /// <summary>Gets the local node ID.</summary>
         public NodeId LocalNode { get; } = NodeId.Parse("test-node");
+        /// <summary>Gets the local roles.</summary>
         public IReadOnlySet<string> LocalRoles { get; } = new HashSet<string>(["driver"]);
+        /// <summary>Determines whether the local node has the specified role.</summary>
+        /// <param name="role">The role to check.</param>
         public bool HasRole(string role) => LocalRoles.Contains(role);
+
+        /// <summary>Gets the members with the specified role.</summary>
+        /// <param name="role">The role to query.</param>
         public IReadOnlyList<NodeId> MembersWithRole(string role) => Array.Empty<NodeId>();
+
+        /// <summary>Gets the leader node for the specified role.</summary>
+        /// <param name="role">The role to query.</param>
         public NodeId? RoleLeader(string role) => null;
+        /// <summary>Raised when the role leader changes.</summary>
         public event EventHandler<RoleLeaderChangedEventArgs>? RoleLeaderChanged
         {
             add { _ = value; }