Improve XML documentation coverage across src modules and sync generated analysis artifacts.

src/NATS.Server/JetStream/Cluster/PlacementEngine.cs

@@ -31,6 +31,11 @@ public static class PlacementEngine
     ///      Overloaded peers are tried only after preferred candidates are exhausted.
     ///   8. Throw InvalidOperationException if fewer than replicas peers can be selected.
     /// </summary>
+    /// <param name="groupName">RAFT group name being placed.</param>
+    /// <param name="replicas">Required number of replicas/peers.</param>
+    /// <param name="availablePeers">Available cluster peers considered for placement.</param>
+    /// <param name="policy">Optional placement policy with cluster/tag constraints.</param>
+    /// <param name="assetCostWeight">Per-asset storage penalty used in scoring.</param>
     public static RaftGroup SelectPeerGroup(
         string groupName,
         int replicas,
@@ -201,10 +206,15 @@ public static class PlacementEngine
 /// </summary>
 public sealed class PeerInfo
 {
+    /// <summary>Unique peer identifier used in RAFT group membership.</summary>
     public required string PeerId { get; init; }
+    /// <summary>Cluster name/partition where this peer resides.</summary>
     public string Cluster { get; set; } = string.Empty;
+    /// <summary>Capability and topology tags advertised by this peer.</summary>
     public HashSet<string> Tags { get; init; } = new(StringComparer.OrdinalIgnoreCase);
+    /// <summary>Whether this peer is currently eligible for new assignments.</summary>
     public bool Available { get; set; } = true;
+    /// <summary>Approximate remaining storage available for new assets.</summary>
     public long AvailableStorage { get; set; } = long.MaxValue;
 
     /// <summary>
@@ -228,8 +238,11 @@ public sealed class PeerInfo
 /// </summary>
 public sealed class PlacementPolicy
 {
+    /// <summary>Optional cluster affinity constraint.</summary>
     public string? Cluster { get; set; }
+    /// <summary>Required tags that must all be present on a candidate peer.</summary>
     public HashSet<string>? Tags { get; set; }
+    /// <summary>Tags that disqualify a candidate peer when present.</summary>
     public HashSet<string>? ExcludeTags { get; set; }
 
     /// <summary>