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/handlers/delivery_replay.go

@@ -2,7 +2,6 @@ package handlers
 
 import (
 	"net/http"
-	"strconv"
 
 	"github.com/go-chi/chi"
 	"gorm.io/gorm"
@@ -329,24 +328,15 @@ func replayBody(body string) *string {
 }
 
 // redirectToEventLog redirects a replay or resubmit back to the event
-// log it was triggered from, carrying the outcome as its notice and
-// the page number the form submitted.
+// log it was triggered from, carrying the outcome as its notice.
 func redirectToEventLog(
 	w http.ResponseWriter,
 	r *http.Request,
 	webhook database.Webhook,
 	code noticeCode,
 ) {
-	dest := withNotice("/hook/"+webhook.ID+"/events", code)
-
-	// The page is read from the form rather than the query string:
-	// this is a POST, and its query string is what logs and Referer
-	// headers record.
-	if page := pageOrFirst(
-		r.PostFormValue("page"),
-	); page > 1 {
-		dest += "&page=" + strconv.Itoa(page)
-	}
-
-	http.Redirect(w, r, dest, http.StatusSeeOther)
+	http.Redirect(
+		w, r, withNotice("/hook/"+webhook.ID+"/events", code),
+		http.StatusSeeOther,
+	)
 }