reminders: store what she says, show it in his clock (V-469)

Two of the four defects on the task.

The stored payload was the whole utterance, so /reminders and the agenda
recited "напомни завтра в 9 утра выпить таблетки" where the reminder is
"выпить таблетки". The marker is an instruction that was already carried out
and the hour is already a column, so reminderBody strips both, and falls back
to the unstripped body whenever stripping would leave nothing — a reminder
that fires and says nothing is worse than a wordy one.

The page rendered the raw {"text":...} envelope and the UTC instant. Both are
now done in mavweb: reminderRows unwraps the payload and formats through
Local(). The unwrap is a copy of store.ReminderText rather than a call to it,
because mavweb builds without CGO and internal/store carries the sqlite
driver — the ipc DTOs are decoupled from the store on purpose.

TestClarifySubjectAnswerFillsRatherThanClobbers asserted the hour survived as
a word in the payload. It now asserts the fire time, which is where the hour
lives.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

cmd/mavweb/main.go

@@ -946,6 +946,51 @@ func deliveryRows(as []ipc.DeliveryAttempt) []deliveryRow {
 	return out
 }
 
+// reminderRow is one line on /reminders, with the payload unwrapped and both
+// timestamps already in his clock.
+//
+// The page rendered `{{.Payload}}` and the UTC instant, so a reminder read
+// `{"text":"выпить таблетки"}` and fired an hour off what he was told
+// (Vikunja #469). Neither is a formatting nicety: the envelope is an internal
+// shape he never chose, and a time on a page he reads is the time on his wall.
+type reminderRow struct {
+	Created string
+	Fires   string
+	Status  string
+	Text    string
+}
+
+// reminderText unwraps the {"text":...} payload the router writes.
+//
+// A copy of store.ReminderText rather than a call to it, because mavweb is one
+// of the pure-Go daemons and internal/store carries the CGO sqlite driver. The
+// ipc DTO is decoupled from the store on purpose, so the unwrap belongs to
+// whoever renders it. Payload that is not that shape is shown as he said it.
+func reminderText(payload string) string {
+	var m map[string]any
+	if err := json.Unmarshal([]byte(payload), &m); err == nil {
+		if t, ok := m["text"]; ok {
+			if s, isStr := t.(string); isStr && s != "" {
+				return s
+			}
+		}
+	}
+	return strings.TrimSpace(payload)
+}
+
+func reminderRows(rs []ipc.Reminder) []reminderRow {
+	out := make([]reminderRow, 0, len(rs))
+	for _, r := range rs {
+		out = append(out, reminderRow{
+			Created: r.CreatedTs.Local().Format("02 Jan 15:04"),
+			Fires:   r.FireTs.Local().Format("02 Jan 15:04"),
+			Status:  r.Status,
+			Text:    reminderText(r.Payload),
+		})
+	}
+	return out
+}
+
 func handleReminders(w http.ResponseWriter, r *http.Request, core ipc.CoreAPI) {
 	if core == nil {
 		http.Error(w, "reminders disabled (no -core)", http.StatusServiceUnavailable)
@@ -959,7 +1004,7 @@ func handleReminders(w http.ResponseWriter, r *http.Request, core ipc.CoreAPI) {
 		return
 	}
 	w.Header().Set("Content-Type", "text/html; charset=utf-8")
-	if err := remindersTmpl.Execute(w, map[string]any{"Reminders": reminders}); err != nil {
+	if err := remindersTmpl.Execute(w, map[string]any{"Reminders": reminderRows(reminders)}); err != nil {
 		log.Printf("reminders template: %v", err)
 	}
 }