feat(todo): places are watched by a quiet service, and asked to notify (ADR 0033, D32)

The first walk showed two faults. Android gives a proximity alert of an
app in the background a fix every 30 minutes (17:04:38, then 17:34:43 on
the Pixel), so a short stop goes unseen. And the place did remind, at
17:36:43, but nothing had asked to notify, so Android showed nothing.

A foreground service of the type location now takes its own fixes while
places wait, under the quietest notification there is: as long as
reaching the nearest circle takes at 30 m/s, doubled while the phone
lies still, between 30 s and 5 min. A place with a reminder asks to
notify as any reminder does.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

apps/todo/halkyon_todo_flutter/lib/l10n/app_de.arb

@@ -292,6 +292,8 @@
   "locationRemindArrive": "Beim Ankommen",
   "locationRemindLeave": "Beim Verlassen",
   "locationRemove": "Entfernen",
+  "locationWatching": "Achtet auf deine Orte",
+  "locationWatchingChannel": "Überwachte Orte",
   "locationAccessTitle": "Standort immer erlauben",
   "locationAccessHint": "Damit Halkyon Todo dich beim Ankommen oder Verlassen erinnert, braucht es deinen Standort auch, wenn es geschlossen ist. Er bleibt auf diesem Gerät. Wähle als Nächstes „Immer zulassen“.",
   "locationAccessGo": "Weiter",