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/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,