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/Dashboard/DashboardConnectionStringDisplay.cs

@@ -6,6 +6,7 @@ public static class DashboardConnectionStringDisplay
 {
     /// <summary>Returns a sanitized Galaxy Repository connection string for display.</summary>
     /// <param name="connectionString">The connection string to sanitize.</param>
+    /// <returns>A connection string with only display-safe fields, or a placeholder if it cannot be parsed.</returns>
     public static string GalaxyRepositoryConnectionString(string connectionString)
     {
         try