docs(src): add missing XML docs and strip tracking-ID comments

Sweep of 203 source files resolving CommentChecker findings: add
<summary>/<param>/<returns>/<inheritdoc> where missing, and remove
resolved task/issue tracking markers (Tests-NNN, Worker-NNN, Server-NNN,
Task N) from code comments. Comment/doc-only — no logic changes.
Server+Tests build clean under TreatWarningsAsErrors.

src/ZB.MOM.WW.MxGateway.Server/Diagnostics/AuthStoreHealthCheck.cs

@@ -12,9 +12,15 @@ public sealed class AuthStoreHealthCheck : IHealthCheck
 {
     private readonly AuthSqliteConnectionFactory _connectionFactory;
 
+    /// <summary>Initializes a new instance of the <see cref="AuthStoreHealthCheck"/> class.</summary>
+    /// <param name="connectionFactory">Factory used to open connections to the SQLite auth store.</param>
     public AuthStoreHealthCheck(AuthSqliteConnectionFactory connectionFactory) =>
         _connectionFactory = connectionFactory ?? throw new ArgumentNullException(nameof(connectionFactory));
 
+    /// <summary>Verifies the SQLite auth store is reachable by executing a trivial query.</summary>
+    /// <param name="context">The health check context.</param>
+    /// <param name="cancellationToken">Token to cancel the asynchronous operation.</param>
+    /// <returns>Healthy when the store responds; otherwise Unhealthy with the underlying exception.</returns>
     public async Task<HealthCheckResult> CheckHealthAsync(
         HealthCheckContext context,
         CancellationToken cancellationToken = default)

src/ZB.MOM.WW.MxGateway.Server/Diagnostics/GatewayLogRedactor.cs

@@ -19,6 +19,7 @@ public static class GatewayLogRedactor
     /// Determines whether a command method bears credentials.
     /// </summary>
     /// <param name="commandMethod">The command method name to check.</param>
+    /// <returns><see langword="true"/> if the command method carries credentials; otherwise <see langword="false"/>.</returns>
     public static bool IsCredentialBearingCommand(string? commandMethod)
     {
         return commandMethod is not null
@@ -29,6 +30,7 @@ public static class GatewayLogRedactor
     /// Redacts the API key secret portion of a Bearer authorization header.
     /// </summary>
     /// <param name="authorizationHeader">The authorization header value to redact.</param>
+    /// <returns>The header with the secret portion redacted, or the original value when it is null, blank, or not a Bearer header.</returns>
     public static string? RedactApiKey(string? authorizationHeader)
     {
         if (string.IsNullOrWhiteSpace(authorizationHeader))
@@ -62,6 +64,7 @@ public static class GatewayLogRedactor
     /// Redacts the client identity if it contains an API key.
     /// </summary>
     /// <param name="clientIdentity">The client identity string to redact.</param>
+    /// <returns>The redacted client identity, or the original value when it contains no API key.</returns>
     public static string? RedactClientIdentity(string? clientIdentity)
     {
         if (string.IsNullOrWhiteSpace(clientIdentity))
@@ -80,6 +83,7 @@ public static class GatewayLogRedactor
     /// <param name="commandMethod">The command method name to check for credentials.</param>
     /// <param name="value">The command value to redact.</param>
     /// <param name="valueLoggingEnabled">Whether value logging is enabled.</param>
+    /// <returns>The redacted placeholder, the original value, or <see langword="null"/> when <paramref name="value"/> is null.</returns>
     public static object? RedactCommandValue(
         string? commandMethod,
         object? value,

src/ZB.MOM.WW.MxGateway.Server/Diagnostics/GatewayLogScope.cs

@@ -8,6 +8,7 @@ public sealed record GatewayLogScope(
     string? ClientIdentity = null)
 {
     /// <summary>Converts the log scope to a dictionary with redacted sensitive fields.</summary>
+    /// <returns>A dictionary containing only the scope's present fields, with sensitive values redacted.</returns>
     public IReadOnlyDictionary<string, object?> ToDictionary()
     {
         Dictionary<string, object?> values = [];

src/ZB.MOM.WW.MxGateway.Server/Diagnostics/GatewayRequestLoggingMiddlewareExtensions.cs

@@ -19,6 +19,7 @@ public static class GatewayRequestLoggingMiddlewareExtensions
 
     /// <summary>Adds gateway request logging scope middleware that reads correlation headers and redacts sensitive data.</summary>
     /// <param name="app">Application builder.</param>
+    /// <returns>The same <see cref="IApplicationBuilder"/>, for chaining.</returns>
     public static IApplicationBuilder UseGatewayRequestLoggingScope(this IApplicationBuilder app)
     {
         ArgumentNullException.ThrowIfNull(app);