Store and show an event's query string, and pass it on to an HTTP target when set (closes #312)

The receiver dropped the query string of every request it received, so a sender's URL parameters were silently lost. Each event now keeps it, as sent, in a new `raw_query` column of the per-webhook `events` table; a resubmitted copy carries its original's. The event log and the event's page show it in the shared request block, the event log leaving out one over 32 KiB with a link, as for headers. The archive and log targets carry it. HTTP targets gain "Pass the query string on to this target", off by default: on, deliveries, replays and resubmits append it to the target URL, joined with `&` to one already there. The access log still hides it.

Model: opus-5-5

internal/handlers/event_log.go

@@ -324,7 +324,8 @@ func loadEventLogRows(
 	var rows []eventLogRow
 
 	err = eventsWithStatus(webhookDB, webhookID, statuses).Select(
-		eventLogColumns, maxRenderedBodyBytes, maxRenderedBodyBytes,
+		eventLogColumns,
+		maxRenderedBodyBytes, maxRenderedBodyBytes, maxRenderedBodyBytes,
 	).Order("created_at DESC").Limit(recentEventLimit).Find(&rows).Error
 
 	return rows, totalEvents, err