Event log: only the newest event expanded, and only the 50 most recent (closes #349)

The event log now loads the 50 newest events in its query and opens
only the newest on load, as the recent events on a webhook's page
already do. With 50 at most there is never a second page, so paging is
gone: the page links, the `page` query parameter, the page number that
Replay and Resubmit carried back to the log, and `pageOrFirst` with its
test. The count beside the heading reads "50 most recent of N events"
when there are more. The comments and README lines that named `page` as
the query parameter the service reads now name `next` and `notice`.

Model: opus-5-5

internal/server/routes_test.go

@@ -1379,9 +1379,9 @@ func TestHook_ResubmitFromEventLog(t *testing.T) {
 
 // TestHook_LinksBetweenPages follows each link to a webhook page that
 // the tests above do not: the navbar's "Webhooks" links, the back and
-// Cancel links, the list's link to a webhook, the "Full Event Log"
-// link beside the recent events, and the event log's page links. Each
-// must point where it should, and that page must render.
+// Cancel links, the list's link to a webhook, and the "Full Event Log"
+// link beside the recent events. Each must point where it should, and
+// that page must render.
 func TestHook_LinksBetweenPages(t *testing.T) {
 	t.Parallel()
 
@@ -1392,12 +1392,6 @@ func TestHook_LinksBetweenPages(t *testing.T) {
 	wh := env.seedWebhook(t, userID)
 	tgt := env.seedTarget(t, wh.ID)
 
-	// The event log shows 25 events a page; one more gives it a second
-	// page, so it renders its Next and Previous links.
-	for range 26 {
-		env.seedEvent(t, wh.ID, "paged")
-	}
-
 	list := "/hooks"
 	newForm := list + "/new"
 	page := "/hook/" + wh.ID
@@ -1429,8 +1423,6 @@ func TestHook_LinksBetweenPages(t *testing.T) {
 		{targetEdit, back, page},
 		{targetEdit, cancel, page},
 		{events, back, page},
-		{events, `href="([^"]+)"[^>]*>Next &rarr;<`, events + "?page=2"},
-		{events + "?page=2", `href="([^"]+)"[^>]*>&larr; Previous<`, events + "?page=1"},
 	} {
 		got := env.urlFrom(t, link.from, link.pattern, cookies)
 		assert.Equal(t, link.want, got, "%s: %s", link.from, link.pattern)