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/reminders.html

@@ -3,10 +3,10 @@
 {{if .Reminders}}<div class=scroll><table>
 <tr><th>created</th><th>fires</th><th>status</th><th>what</th></tr>
 {{range .Reminders}}<tr>
-<td class=hint>{{.CreatedTs.Format "02 Jan 15:04"}}</td>
-<td>{{.FireTs.Format "02 Jan 15:04"}}</td>
+<td class=hint>{{.Created}}</td>
+<td>{{.Fires}}</td>
 <td><span class="badge {{.Status}}">{{.Status}}</span></td>
-<td class=text-max>{{.Payload}}</td>
+<td class=text-max>{{.Text}}</td>
 </tr>{{end}}</table></div>
 {{else}}<div class=empty>
   <svg class=icon width="24" height="24"><use href="/ethos-icons.svg#i-calendar"/></svg>