test(auditlog): cover ExecutionId in AuditEvent round-trip test; clarify staging-table comment

src/ScadaLink.ConfigurationDatabase/Repositories/AuditLogRepository.cs

@@ -268,6 +268,9 @@ VALUES
                 PayloadTruncated   bit              NOT NULL,
                 Extra              nvarchar(max)    NULL,
                 ForwardState       varchar(32)      NULL,
+                -- ExecutionId is last because it was added to the live AuditLog table by a later
+                -- ALTER TABLE ADD migration; the staging table must match the live table column
+                -- shape ordinal-for-ordinal or ALTER TABLE ... SWITCH PARTITION fails.
                 ExecutionId        uniqueidentifier NULL,
                 CONSTRAINT PK_{stagingTableName} PRIMARY KEY CLUSTERED (EventId, OccurredAtUtc)
             ) ON [PRIMARY];