docs(xmldoc): fill missing XML docs + strip tracking-ID comments across src

Adds <summary>/<param>/<returns>/<inheritdoc> where missing and removes
project bookkeeping IDs (task/tracking refs) from shipped code comments,
so the docs read cleanly and CommentChecker is quiet except for known
false positives (PLC/protocol terms, event/IEqualityComparer inheritdoc).
Doc/comment-only; no logic changed; solution builds clean.

src/Server/ZB.MOM.WW.OtOpcUa.ControlPlane/AdminOperations/ConfigComposer.cs

@@ -25,6 +25,7 @@ public static class ConfigComposer
     /// <summary>Reads the current configuration and returns a deterministic snapshot blob with revision hash.</summary>
     /// <param name="db">The configuration database context.</param>
     /// <param name="ct">The cancellation token for the operation.</param>
+    /// <returns>A deterministic <see cref="ConfigArtifact"/> containing the serialised snapshot bytes and its revision hash.</returns>
     public static async Task<ConfigArtifact> SnapshotAndFlattenAsync(
         OtOpcUaConfigDbContext db, CancellationToken ct = default)
     {
@@ -53,6 +54,7 @@ public static class ConfigComposer
 
     /// <summary>Returns the SHA-256 hex digest of the supplied artifact bytes (lowercase, no prefix).</summary>
     /// <param name="blob">The bytes to hash.</param>
+    /// <returns>The lowercase hex-encoded SHA-256 digest.</returns>
     public static string HashOf(ReadOnlySpan<byte> blob) =>
         Convert.ToHexStringLower(SHA256.HashData(blob));
 }