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.Tests/Gateway/Dashboard/DashboardGroupRoleMapperTests.cs

@@ -35,6 +35,7 @@ public sealed class DashboardGroupRoleMapperTests
     /// <summary>Verifies full-DN match, leading-RDN fallback, case-insensitivity, and unmapped → empty.</summary>
     /// <param name="ldapGroup">The LDAP group name or distinguished name.</param>
     /// <param name="expectedRole">The expected role or null if no match.</param>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Theory]
     [InlineData("GwAdmin", DashboardRoles.Admin)]
     [InlineData("gwadmin", DashboardRoles.Admin)]
@@ -61,6 +62,7 @@ public sealed class DashboardGroupRoleMapperTests
     }
 
     /// <summary>Verifies that admin and viewer roles are both emitted when both groups are present.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task MapAsync_AdminPlusViewer_BothRolesEmitted()
     {
@@ -75,6 +77,7 @@ public sealed class DashboardGroupRoleMapperTests
     }
 
     /// <summary>Verifies that an empty GroupToRole map yields no roles.</summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task MapAsync_EmptyMapping_ReturnsNoRoles()
     {
@@ -86,12 +89,13 @@ public sealed class DashboardGroupRoleMapperTests
     }
 
     /// <summary>
-    /// Task 1.7 (canonical roles): an LDAP user in the admin group must resolve
+    /// Canonical roles: an LDAP user in the admin group must resolve
     /// to the canonical role value <c>"Administrator"</c> (not the legacy
     /// <c>"Admin"</c>), and the reader group to <c>"Viewer"</c>. Asserted with
     /// string LITERALS — independent of <see cref="DashboardRoles"/> — so a
     /// regression on the constant's value is caught here.
     /// </summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task MapAsync_AdminGroup_ResolvesToCanonicalAdministratorValue()
     {
@@ -105,7 +109,7 @@ public sealed class DashboardGroupRoleMapperTests
     }
 
     /// <summary>
-    /// Task 1.7: the canonical admin value (<c>"Administrator"</c>) passes the
+    /// The canonical admin value (<c>"Administrator"</c>) passes the
     /// admin-only gate while a <c>"Viewer"</c> fails it — asserted with literals,
     /// proving enforcement is bound to the new value and the legacy <c>"Admin"</c>
     /// string is no longer what authorizes admin actions.
@@ -124,6 +128,7 @@ public sealed class DashboardGroupRoleMapperTests
     /// Verifies the extracted shared helper is the single source of truth: it
     /// produces the same roles the mapper does for the same inputs.
     /// </summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
     [Fact]
     public async Task SharedHelper_MatchesMapperOutput()
     {