Give each event its own page and show bodies the same everywhere (closes #369)

Each row of the recent events on the webhook page links to the
event's own page, /hook/{id}/events/{eventID}, and expands to show its
body; only the newest starts expanded. The event's page shows its
details, its whole body and every delivery with its attempts.

One renderer, newBodyView with templates/event_body.html, shows a body
in all three places: whole up to 32 KiB, cut there in the lists with a
link to the event's page, JSON pretty-printed, a body of more than 200
lines or 32 KiB in a scrolling box, and a body that is not text left
out beside its download link. A resubmitted copy links to its
original's page.

Model: opus-5-5

internal/handlers/source_management.go

@@ -1022,10 +1022,10 @@ func (h *Handlers) HandleSourceLogs() http.HandlerFunc {
 // view, which renders its target as a blank name.
 //
 // This map is historical display only. It is built for the event
-// log page and reaches nothing but DeliveryView.Target: the
-// target list on the source detail page, the edit form and the
-// replay path each resolve targets themselves, and a deleted row
-// is refused there as before.
+// log and an event's own page, and reaches nothing but
+// DeliveryView.Target: the target list on the source detail page,
+// the edit form and the replay path each resolve targets
+// themselves, and a deleted row is refused there as before.
 func (h *Handlers) loadTargetMap(
 	webhookID string,
 ) (map[string]eventLogTarget, error) {
@@ -1081,10 +1081,8 @@ func (h *Handlers) loadEventsWithDeliveries(
 	targetMap map[string]eventLogTarget,
 	page int,
 ) ([]EventLogView, int64, bool) {
-	var result []EventLogView
-
 	if !h.dbMgr.DBExists(webhook.ID) {
-		return result, 0, true
+		return nil, 0, true
 	}
 
 	webhookDB, err := h.dbMgr.GetDB(webhook.ID)
@@ -1100,7 +1098,26 @@ func (h *Handlers) loadEventsWithDeliveries(
 		webhookDB, webhook.ID, page,
 	)
 
-	result = make([]EventLogView, len(rows))
+	result, ok := h.eventLogViews(
+		w, r, webhookDB, webhook.ID, rows, targetMap,
+	)
+
+	return result, totalEvents, ok
+}
+
+// eventLogViews projects loaded events for rendering, each with
+// its deliveries and how many times it has been resubmitted. Like
+// loadEventsWithDeliveries, it reports false once it has answered
+// the request with an error.
+func (h *Handlers) eventLogViews(
+	w http.ResponseWriter,
+	r *http.Request,
+	webhookDB *gorm.DB,
+	webhookID string,
+	rows []eventLogRow,
+	targetMap map[string]eventLogTarget,
+) ([]EventLogView, bool) {
+	result := make([]EventLogView, len(rows))
 	eventDeliveries := make([][]database.Delivery, len(rows))
 
 	var deliveryIDs []string
@@ -1108,7 +1125,7 @@ func (h *Handlers) loadEventsWithDeliveries(
 	eventIDs := make([]string, len(rows))
 
 	for i := range rows {
-		result[i] = rows[i].view()
+		result[i] = rows[i].view(webhookID)
 		eventIDs[i] = rows[i].ID
 
 		webhookDB.Where(
@@ -1130,7 +1147,7 @@ func (h *Handlers) loadEventsWithDeliveries(
 			w, r, "failed to load delivery attempts", err,
 		)
 
-		return nil, 0, false
+		return nil, false
 	}
 
 	resubmits, err := resubmitCounts(webhookDB, eventIDs)
@@ -1139,7 +1156,7 @@ func (h *Handlers) loadEventsWithDeliveries(
 			w, r, "failed to count event resubmissions", err,
 		)
 
-		return nil, 0, false
+		return nil, false
 	}
 
 	for i := range rows {
@@ -1149,7 +1166,7 @@ func (h *Handlers) loadEventsWithDeliveries(
 		result[i].ResubmitCount = resubmits[rows[i].ID]
 	}
 
-	return result, totalEvents, true
+	return result, true
 }
 
 // loadEventLogRows reads one page of the event log projection, newest