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",

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

@@ -988,6 +988,8 @@
   "@locationRemove": {
     "description": "A task's location's menu."
   },
+  "locationWatching": "Watching your places",
+  "locationWatchingChannel": "Places watched",
   "locationAccessTitle": "Allow location all the time",
   "@locationAccessTitle": {
     "description": "Before asking for the position in the background."

apps/todo/halkyon_todo_flutter/lib/l10n/app_localizations.dart

@@ -1852,6 +1852,18 @@ abstract class AppLocalizations {
   /// **'Remove'**
   String get locationRemove;
 
+  /// No description provided for @locationWatching.
+  ///
+  /// In en, this message translates to:
+  /// **'Watching your places'**
+  String get locationWatching;
+
+  /// No description provided for @locationWatchingChannel.
+  ///
+  /// In en, this message translates to:
+  /// **'Places watched'**
+  String get locationWatchingChannel;
+
   /// Before asking for the position in the background.
   ///
   /// In en, this message translates to:

apps/todo/halkyon_todo_flutter/lib/l10n/app_localizations_de.dart

@@ -1141,6 +1141,12 @@ class AppLocalizationsDe extends AppLocalizations {
   @override
   String get locationRemove => 'Entfernen';
 
+  @override
+  String get locationWatching => 'Achtet auf deine Orte';
+
+  @override
+  String get locationWatchingChannel => 'Überwachte Orte';
+
   @override
   String get locationAccessTitle => 'Standort immer erlauben';
 

apps/todo/halkyon_todo_flutter/lib/l10n/app_localizations_en.dart

@@ -1140,6 +1140,12 @@ class AppLocalizationsEn extends AppLocalizations {
   @override
   String get locationRemove => 'Remove';
 
+  @override
+  String get locationWatching => 'Watching your places';
+
+  @override
+  String get locationWatchingChannel => 'Places watched';
+
   @override
   String get locationAccessTitle => 'Allow location all the time';
 

apps/todo/halkyon_todo_flutter/lib/src/feature/location/data/location_reminder_gateway.dart

@@ -12,16 +12,23 @@ enum LocationAccess() {
 /// A point on the map.
 typedef LatLon = ({double lat, double lon});
 
-/// Where the device watches places: the system's proximity alerts on Android
-/// alone, with no Google services, on the device, as the instance reads no
-/// task (D32).
+/// Where the device watches places: a foreground service on Android alone,
+/// with no Google services, on the device, as the instance reads no task
+/// (D32).
 abstract interface class LocationReminderGateway() {
   /// Whether this device can watch places at all.
   bool get available;
 
   /// Makes [watches] the places watched, those watched before and no longer
-  /// among them stopped; [channel] names the notifications' kind.
-  Future<void> replace(List<LocationWatch> watches, {required String channel});
+  /// among them stopped; [channel] names the notifications' kind, [watching]
+  /// says what the quiet notification of watching says, [watchingChannel]
+  /// names its kind.
+  Future<void> replace(
+    List<LocationWatch> watches, {
+    required String channel,
+    String watching = '',
+    String watchingChannel = '',
+  });
 
   /// What the device allows now.
   Future<LocationAccess> access();
@@ -49,6 +56,8 @@ class const NoLocationReminders() implements LocationReminderGateway {
   Future<void> replace(
     List<LocationWatch> watches, {
     required String channel,
+    String watching = '',
+    String watchingChannel = '',
   }) async {}
 
   @override
@@ -81,9 +90,13 @@ class const AndroidLocationReminders() implements LocationReminderGateway {
   Future<void> replace(
     List<LocationWatch> watches, {
     required String channel,
+    String watching = '',
+    String watchingChannel = '',
   }) => _channel.invokeMethod<void>('replace', {
     'watches': [for (final watch in watches) watch.toJson()],
     'channel': channel,
+    'watching': watching,
+    'watchingChannel': watchingChannel,
   });
 
   @override

apps/todo/halkyon_todo_flutter/lib/src/feature/reminder/widget/reminder_scheduler.dart

@@ -64,15 +64,16 @@ class _ReminderSchedulerState() extends State<ReminderScheduler> {
     final tasks = [
       for (final task in state.tasks) StoredTask(task.id, task.content),
     ];
-    _watch(tasks);
+    final watching = _watch(tasks);
     final plan = planReminders(tasks, now: clock.now());
     // Asked to notify wherever the reminders came from (D31): typed, added
-    // by the automatic reminder, chosen in a sheet or synced; and read
-    // again as the app comes back, from the system's settings perhaps.
+    // by the automatic reminder, chosen in a sheet or synced, or at a place
+    // (D32); and read again as the app comes back, from the system's
+    // settings perhaps.
     unawaited(
       PersonScope.of<TodoPerson>(
         context,
-      ).notifications.planned(any: plan.isNotEmpty),
+      ).notifications.planned(any: plan.isNotEmpty || watching),
     );
     final snooze = state.settings.reminders.snooze;
     if (listEquals(plan, _planned) && snooze == _snooze) {
@@ -101,8 +102,9 @@ class _ReminderSchedulerState() extends State<ReminderScheduler> {
     );
   }
 
-  /// Hands the places [tasks] remind at to the device, where they changed.
-  void _watch(List<StoredTask> tasks) {
+  /// Hands the places [tasks] remind at to the device, where they changed;
+  /// whether there are any.
+  bool _watch(List<StoredTask> tasks) {
     final l10n = AppLocalizations.of(context);
     final todo = PersonScope.of<TodoPerson>(context);
     final watches = [
@@ -120,9 +122,12 @@ class _ReminderSchedulerState() extends State<ReminderScheduler> {
         todo.locationReminders.replace(
           watches,
           channel: l10n.remindersChannel,
+          watching: l10n.locationWatching,
+          watchingChannel: l10n.locationWatchingChannel,
         ),
       );
     }
+    return watches.isNotEmpty;
   }
 
   @override