fix(configuration): resolve Medium code-review findings (Configuration-002, -003, -006, -009)

Configuration-002: sp_PublishGeneration is transaction-nesting aware
(BEGIN TRANSACTION vs SAVE TRANSACTION on @@TRANCOUNT) so a caller's outer
transaction survives a publish failure; sp_ValidateDraft wrapped in TRY/CATCH.
Configuration-003: ValidatePathLength uses the cluster's actual Enterprise/Site
lengths when available, falling back to the conservative approximation.
Configuration-006: ResilientConfigReader treats a command-timeout
TaskCanceledException as a fault (not caller cancellation) and falls back.
Configuration-009: removed the checked-in plaintext sa connection string;
CreateDbContext now requires OTOPCUA_CONFIG_CONNECTION.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/Core/ZB.MOM.WW.OtOpcUa.Configuration/Validation/DraftSnapshot.cs

@@ -11,6 +11,18 @@ public sealed class DraftSnapshot
     public required long GenerationId { get; init; }
     public required string ClusterId { get; init; }
 
+    /// <summary>
+    ///     Cluster's Enterprise segment (UNS level 1). When set, <see cref="DraftValidator"/> uses
+    ///     the actual length for path-length checks instead of a conservative 32-char upper bound.
+    /// </summary>
+    public string? Enterprise { get; init; }
+
+    /// <summary>
+    ///     Cluster's Site segment (UNS level 2). When set, <see cref="DraftValidator"/> uses the
+    ///     actual length for path-length checks instead of a conservative 32-char upper bound.
+    /// </summary>
+    public string? Site { get; init; }
+
     public IReadOnlyList<Namespace> Namespaces { get; init; } = [];
     public IReadOnlyList<DriverInstance> DriverInstances { get; init; } = [];
     public IReadOnlyList<Device> Devices { get; init; } = [];