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/source_management.go

@@ -11,6 +11,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/dustin/go-humanize"
 	"github.com/go-chi/chi"
 	"github.com/google/uuid"
 	"gorm.io/gorm"
@@ -95,6 +96,14 @@ type DeliveryView struct {
 	Status database.DeliveryStatus
 	Target delivery.TargetView
 
+	// Replay is set on a delivery the Replay action created.
+	Replay bool
+
+	// Created is how long ago the delivery was created, and
+	// CreatedUTC the full timestamp the page shows on hover.
+	Created    string
+	CreatedUTC string
+
 	// Results is this delivery's attempts in attempt order,
 	// bounded by maxRenderedAttempts. Without them a failure
 	// renders as the status word alone and says nothing about
@@ -1430,6 +1439,7 @@ func (h *Handlers) newDeliveryViews(
 	for i := range deliveries {
 		target := targetMap[deliveries[i].TargetID]
 		rows := attempts[deliveries[i].ID]
+		created := deliveries[i].CreatedAt
 
 		results, omitted := renderedAttempts(
 			rows, target.Redactor,
@@ -1439,6 +1449,9 @@ func (h *Handlers) newDeliveryViews(
 			ID:              deliveries[i].ID,
 			Status:          deliveries[i].Status,
 			Target:          target.View,
+			Replay:          deliveries[i].Replay,
+			Created:         humanize.Time(created),
+			CreatedUTC:      created.UTC().Format(time.DateTime) + " UTC",
 			Results:         results,
 			AttemptCount:    len(rows),
 			AttemptsOmitted: omitted,