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/IDashboardBrowseService.cs

@@ -12,11 +12,13 @@ public interface IDashboardBrowseService
 {
     /// <summary>Returns root browse nodes (objects with no parent).</summary>
     /// <param name="filter">Filter arguments forwarded to the projector.</param>
+    /// <returns>The root-level browse nodes and the cache sequence they were projected from.</returns>
     BrowseLevelResult GetRoots(BrowseFilterArgs filter);
 
     /// <summary>Returns the direct children of the given parent gobject id.</summary>
     /// <param name="parentGobjectId">The Galaxy gobject id of the parent to expand.</param>
     /// <param name="filter">Filter arguments forwarded to the projector.</param>
+    /// <returns>The child browse nodes for the requested parent and the cache sequence they were projected from.</returns>
     BrowseLevelResult GetChildren(int parentGobjectId, BrowseFilterArgs filter);
 
     /// <summary>Current Galaxy cache sequence. Bumps after each successful refresh.</summary>