Event log: show attempt and delivery times, label replays, zone event times (closes #386)

Each attempt shows when it was recorded and each delivery when it was
created, in the event log and on the event's page. The event log's
event times read as the recent events list does: how long ago, with
the full UTC time on hover.

A delivery records whether Replay created it, in a new replay column
added to the delivery model in place. Such a delivery is labelled a
replay in the event's summary line and in both pages' delivery lists.

Model: opus-5-5

internal/handlers/delivery_replay_test.go

@@ -3,6 +3,7 @@ package handlers_test
 import (
 	"net/http"
 	"net/http/httptest"
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -528,3 +529,48 @@ func TestHandleSourceLogs_RendersReplayControlAndBanner(t *testing.T) {
 	assert.NotContains(t, unknown, "alert-success")
 	assert.NotContains(t, unknown, "made-up")
 }
+
+// TestHandleDeliveryReplay_LabelsTheReplay proves a delivery created
+// by Replay is labelled as a replay in the event's summary line in the
+// event log, and in the list of the event's deliveries there and on
+// the event's page, while the delivery it repeats is not.
+func TestHandleDeliveryReplay_LabelsTheReplay(t *testing.T) {
+	t.Parallel()
+
+	var (
+		h     *handlers.Handlers
+		sess  *session.Session
+		db    *database.Database
+		dbMgr *database.WebhookDBManager
+	)
+
+	app := newTestApp(t, &h, &sess, &db, &dbMgr)
+	app.RequireStart()
+
+	t.Cleanup(app.RequireStop)
+
+	wh := seedWebhook(t, db)
+	tgt := seedConfiguredTarget(
+		t, db, wh.ID, database.TargetTypeHTTP,
+		`{"url":"`+replayTargetURL+`"}`,
+	)
+
+	event, original := seedFailedDelivery(t, dbMgr, wh.ID, tgt.ID)
+
+	w := postReplay(t, h, sess, wh.ID, original.ID)
+	require.Equal(t, http.StatusSeeOther, w.Code)
+
+	eventLog := renderSourceLogsPage(t, h, sess, wh.ID)
+
+	assert.Contains(t, eventLog, tgt.Name+": failed")
+	assert.Contains(t, eventLog, tgt.Name+" (replay): pending")
+
+	w = serveEventPage(t, h, sess, wh.ID, event.ID)
+	require.Equal(t, http.StatusOK, w.Code)
+
+	const label = `<span class="text-xs text-gray-500">replay</span>`
+
+	for _, page := range []string{eventLog, w.Body.String()} {
+		assert.Equal(t, 1, strings.Count(page, label))
+	}
+}