perf(central): set-based ingest, aligned partition purge, KPI query shapes, EF hygiene

src/ZB.MOM.WW.ScadaBridge.Commons/Interfaces/Repositories/INotificationOutboxRepository.cs

@@ -46,10 +46,25 @@ public interface INotificationOutboxRepository
     Task<Notification?> GetByIdAsync(string notificationId, CancellationToken cancellationToken = default);
 
     /// <summary>
-    /// Marks <paramref name="n"/> modified and persists it (status transitions).
-    /// Commits internally — this call is its own transaction.
+    /// Persists <paramref name="n"/>'s <b>delivery-state</b> columns —
+    /// <c>Status</c>, <c>RetryCount</c>, <c>LastError</c>, <c>ResolvedTargets</c>,
+    /// <c>LastAttemptAt</c>, <c>NextAttemptAt</c>, <c>DeliveredAt</c>. Commits
+    /// internally — this call is its own transaction.
     /// </summary>
-    /// <param name="n">The notification to update.</param>
+    /// <remarks>
+    /// <b>Scope is deliberately narrow.</b> Those seven columns are the ONLY
+    /// mutable state a notification has: everything else (identity, type, list,
+    /// subject, body, type data, source/origin attribution, enqueue and creation
+    /// timestamps) is written once at ingest and is immutable by contract. Every
+    /// caller — the dispatcher's per-attempt write and the operator retry/discard
+    /// one-shots — touches only this set. Implementations are therefore free to
+    /// issue a targeted UPDATE of these columns rather than rewriting the whole
+    /// row, which matters because the row carries <c>nvarchar(max)</c> body and
+    /// payload columns and the dispatcher writes on EVERY attempt. A future
+    /// caller that needs to change an immutable column must add its own method
+    /// rather than widening this one.
+    /// </remarks>
+    /// <param name="n">The notification whose delivery state should be persisted.</param>
     /// <param name="cancellationToken">Cancellation token.</param>
     /// <returns>A task that completes when the notification has been persisted.</returns>
     Task UpdateAsync(Notification n, CancellationToken cancellationToken = default);