docs: strip task-tracking IDs from code comments and fill missing XML docs

Tracking IDs are review bookkeeping that rots in shipped source; the rationale they tagged is kept. Comment-only change (CommentChecker 458 -> 16 false positives).

src/ZB.MOM.WW.MxGateway.Tests/Configuration/PreHostSecretExpansionTests.cs

@@ -18,6 +18,10 @@ namespace ZB.MOM.WW.MxGateway.Tests.Configuration;
 /// </summary>
 public sealed class PreHostSecretExpansionTests
 {
+    /// <summary>
+    /// A seeded secret reference in configuration resolves to its plaintext.
+    /// </summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task ExpandConfiguration_SeededReference_ResolvesToPlaintext()
     {
@@ -37,6 +41,7 @@ public sealed class PreHostSecretExpansionTests
     /// <c>${secret:ldap/mxgateway/bind}</c>. Proves that exact reference at that exact key resolves to
     /// the seeded plaintext through the same pre-host expander the host runs.
     /// </summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task ExpandConfiguration_LdapBindReference_ResolvesToSeededPassword()
     {
@@ -52,6 +57,10 @@ public sealed class PreHostSecretExpansionTests
         Assert.Equal(bindPassword, config["MxGateway:Ldap:ServiceAccountPassword"]);
     }
 
+    /// <summary>
+    /// A reference to an absent secret throws instead of leaving the token in place.
+    /// </summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task ExpandConfiguration_MissingReference_ThrowsFailClosed()
     {
@@ -81,8 +90,11 @@ public sealed class PreHostSecretExpansionTests
             _envVarName = envVarName;
         }
 
+        /// <summary>Gets the secret resolver from the fixture's DI graph.</summary>
         public ISecretResolver Resolver => _provider.GetRequiredService<ISecretResolver>();
 
+        /// <summary>Creates a fixture with a unique SQLite store and master-key environment variable.</summary>
+        /// <returns>The migrated fixture.</returns>
         public static SecretsFixture Create()
         {
             string unique = Guid.NewGuid().ToString("N");
@@ -111,8 +123,13 @@ public sealed class PreHostSecretExpansionTests
             return new SecretsFixture(provider, sqlitePath, envVarName);
         }
 
-        // Seals a plaintext value under a fresh DEK and upserts it — the same store/cipher pair the
-        // CLI 'secret set' verb uses.
+        /// <summary>
+        /// Seals a plaintext value under a fresh DEK and upserts it, using the same store/cipher pair
+        /// the CLI 'secret set' verb uses.
+        /// </summary>
+        /// <param name="name">The secret name.</param>
+        /// <param name="plaintext">The plaintext value to store.</param>
+        /// <returns>A task that represents the asynchronous operation.</returns>
         public async Task SeedAsync(string name, string plaintext)
         {
             var secretName = new SecretName(name);
@@ -122,11 +139,15 @@ public sealed class PreHostSecretExpansionTests
             await store.UpsertAsync(sealed_, default);
         }
 
+        /// <summary>Builds an in-memory configuration from the given key/value pairs.</summary>
+        /// <param name="entries">The configuration entries.</param>
+        /// <returns>The built configuration root.</returns>
         public IConfigurationRoot BuildConfig(params (string Key, string Value)[] entries) =>
             new ConfigurationBuilder()
                 .AddInMemoryCollection(entries.ToDictionary(e => e.Key, e => (string?)e.Value))
                 .Build();
 
+        /// <summary>Disposes the service provider and clears the test environment variable.</summary>
         public void Dispose()
         {
             _provider.Dispose();