perf(runtime): O(1) attribute resolution, precomputed types, coalesced static writes, shared JSON options

src/ZB.MOM.WW.ScadaBridge.SiteRuntime/Persistence/SiteStorageService.cs

@@ -345,6 +345,53 @@ public class SiteStorageService
         await command.ExecuteNonQueryAsync();
     }
 
+    /// <summary>
+    /// Batch counterpart of <see cref="SetStaticOverrideAsync"/> (perf remediation,
+    /// arch-review WP1.5): upserts a set of static attribute overrides for one instance
+    /// in a SINGLE connection + transaction with one prepared command re-bound per row.
+    /// Used by the InstanceActor's coalesced flush — mirrors NativeAlarmActor's
+    /// MarkDirtyUpsert/FlushDirtyUpserts (P4) pattern — so a burst of rapid SetAttribute
+    /// calls on an instance collapses into one batched write instead of a write per call.
+    /// </summary>
+    /// <param name="instanceName">The unique name of the instance.</param>
+    /// <param name="overrides">The attribute name/value pairs to upsert (latest value per name).</param>
+    /// <returns>A task that completes when all rows have been committed.</returns>
+    public async Task SetStaticOverridesAsync(
+        string instanceName, IReadOnlyList<(string AttributeName, string Value)> overrides)
+    {
+        if (overrides.Count == 0)
+            return;
+
+        await using var connection = OpenConnection();
+        await using var transaction = (SqliteTransaction)await connection.BeginTransactionAsync();
+
+        await using var command = connection.CreateCommand();
+        command.Transaction = transaction;
+        command.CommandText = @"
+            INSERT INTO static_attribute_overrides (instance_unique_name, attribute_name, override_value, updated_at)
+            VALUES (@name, @attr, @val, @updatedAt)
+            ON CONFLICT(instance_unique_name, attribute_name) DO UPDATE SET
+                override_value = excluded.override_value,
+                updated_at     = excluded.updated_at";
+
+        var pName = command.Parameters.Add("@name", SqliteType.Text);
+        var pAttr = command.Parameters.Add("@attr", SqliteType.Text);
+        var pVal = command.Parameters.Add("@val", SqliteType.Text);
+        var pUpdatedAt = command.Parameters.Add("@updatedAt", SqliteType.Text);
+        pName.Value = instanceName;
+
+        var updatedAt = DateTimeOffset.UtcNow.ToString("O");
+        foreach (var (attributeName, value) in overrides)
+        {
+            pAttr.Value = attributeName;
+            pVal.Value = value;
+            pUpdatedAt.Value = updatedAt;
+            await command.ExecuteNonQueryAsync();
+        }
+
+        await transaction.CommitAsync();
+    }
+
     /// <summary>
     /// Clears all static attribute overrides for an instance.
     /// Called on redeployment to reset overrides.