Add saved places and optional device location

A saved place is a named point the user keeps: it frames the map now, and once
the worker publishes station data it is what the nearest-station readings and,
later, the rain notifications will hang off. Free points rather than stations,
because people think in terms of home and work, not in terms of which weather
station happens to represent them.

Everything stays on the device. Places live in SharedPreferences under a
versioned key, and there is no account to attach them to and no server that
would accept them. That is what keeps the Data safety declaration able to say
no location is collected, and it must survive the notification work: the device
will subscribe to the topic for the cell containing a place, so the link
between a person and a place never leaves their phone.

Location is coarse only, and that took enforcing. geolocator declares
ACCESS_FINE_LOCATION in its own manifest and the merger pulls it in, so the
system dialog offered "Precise" despite the app asking for nothing of the sort;
the manifest now removes it with tools:node="remove", and the dialog reads
"approximate location" with no choice offered. Requests also go through the
platform LocationManager rather than the Play Services fused provider, which
prompts about Location Accuracy and, when declined, returns no fix at all —
an absurd outcome for an app that only ever wanted an approximate one, and one
that also tied location to Play Services being present.

The prominent disclosure comes before the system dialog, as Play requires, and
is repeated in Settings so someone who already answered can still read what the
permission is for. Declining leaves the app fully usable.

Two more defects found by running it and by a test:

- MapLibreMap leaves cameraPosition null unless trackCameraPosition is set, so
  "save the map centre" silently saved the region default rather than what the
  user was looking at.
- Place ids came straight from the microsecond clock, so two places saved in
  the same microsecond shared an id and rename, remove and the duplicate-name
  check all acted on the wrong one. A test caught it on a fast machine.

Saving refuses points outside the region rather than accepting them: a place in
Rome would look like it worked and then show nothing forever.

Also corrects CLAUDE.md, which still said ARPA states no licence, and records
the ARPA realtime API there with the property that governs how it may be used —
it lags about 4.5 hours, so it is an observation archive and must never sit
next to 5-minute radar looking current.

Verified: analyze clean, 158 tests passing, and on the emulator the disclosure
precedes the system dialog, the dialog asks only for approximate location, a
place survives restart and reinstall, and tapping one moves the map onto it.

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

Nuvolari/app/lib/features/map/radar_map_screen.dart

@@ -5,11 +5,17 @@ import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:maplibre_gl/maplibre_gl.dart';
 
 import '../../core/config/env.dart';
+import '../../core/region/geo.dart';
 import '../../core/region/region_config.dart';
 import '../../core/region/region_repository.dart';
 import '../../data/radar/radar_manifest.dart';
 import '../../data/radar/radar_source.dart';
 import '../../l10n/app_localizations.dart';
+import '../places/location_flow.dart';
+import '../places/places_screen.dart';
+import '../places/saved_place.dart';
+import '../places/saved_places.dart';
+import '../settings/settings_screen.dart';
 import '../timeline/data_age_banner.dart';
 import '../timeline/radar_timeline.dart';
 import '../timeline/timeline_bar.dart';
@@ -17,6 +23,119 @@ import 'attribution_bar.dart';
 import 'map_style.dart';
 import 'radar_overlay.dart';
 
+/// The live map controller, or null before the map is created.
+///
+/// Held in a provider because the app bar sits above the map in the widget tree
+/// and still needs to move the camera. Cleared on dispose so a stale controller
+/// is never used after the map is gone.
+class MapControllerHolder extends Notifier<MapLibreMapController?> {
+  @override
+  MapLibreMapController? build() => null;
+
+  void attach(MapLibreMapController controller) => state = controller;
+
+  void detach() => state = null;
+}
+
+final mapControllerProvider =
+    NotifierProvider<MapControllerHolder, MapLibreMapController?>(
+      MapControllerHolder.new,
+    );
+
+/// Moves the map onto [point], keeping the current zoom.
+Future<void> _centreOn(WidgetRef ref, GeoPoint point) async {
+  final controller = ref.read(mapControllerProvider);
+  if (controller == null) return;
+  await controller.animateCamera(
+    CameraUpdate.newLatLng(LatLng(point.latitude, point.longitude)),
+  );
+}
+
+/// Centres the map on the device position.
+class _LocateAction extends ConsumerWidget {
+  const _LocateAction();
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    final l10n = AppLocalizations.of(context);
+
+    return IconButton(
+      tooltip: l10n.locateMe,
+      icon: const Icon(Icons.my_location),
+      onPressed: () async {
+        final point = await requestPosition(context, ref);
+        if (point == null || !context.mounted) return;
+
+        // The app only has data for this region. Saying so beats silently
+        // refusing to move, and beats moving somewhere with an empty map.
+        final region = await ref.read(regionConfigProvider.future);
+        if (!context.mounted) return;
+        if (!region.bounds.contains(point)) {
+          ScaffoldMessenger.of(
+            context,
+          ).showSnackBar(SnackBar(content: Text(l10n.locationOutsideRegion)));
+          return;
+        }
+
+        ref.read(activePlaceProvider.notifier).select(null);
+        await _centreOn(ref, point);
+      },
+    );
+  }
+}
+
+/// Opens the saved places list and centres on whatever comes back.
+class _PlacesAction extends ConsumerWidget {
+  const _PlacesAction();
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    final l10n = AppLocalizations.of(context);
+
+    return IconButton(
+      tooltip: l10n.placesOpen,
+      icon: const Icon(Icons.place_outlined),
+      onPressed: () async {
+        final controller = ref.read(mapControllerProvider);
+        final region = await ref.read(regionConfigProvider.future);
+        if (!context.mounted) return;
+
+        final target = controller?.cameraPosition?.target;
+        final centre = target == null
+            ? region.map.center
+            : GeoPoint(target.longitude, target.latitude);
+
+        final chosen = await Navigator.of(context).push<SavedPlace>(
+          MaterialPageRoute<SavedPlace>(
+            builder: (_) => PlacesScreen(mapCentre: centre),
+          ),
+        );
+        if (chosen == null) return;
+
+        ref.read(activePlaceProvider.notifier).select(chosen);
+        await _centreOn(ref, chosen.point);
+      },
+    );
+  }
+}
+
+class _SettingsAction extends StatelessWidget {
+  const _SettingsAction();
+
+  @override
+  Widget build(BuildContext context) {
+    final l10n = AppLocalizations.of(context);
+
+    return IconButton(
+      tooltip: l10n.settingsOpen,
+      icon: const Icon(Icons.settings_outlined),
+      onPressed: () => Navigator.of(
+        context,
+      ).push(MaterialPageRoute<void>(builder: (_) => const SettingsScreen())),
+    );
+  }
+}
+
 /// The radar map: base map, animated precipitation overlay, timeline.
 class RadarMapScreen extends ConsumerWidget {
   const RadarMapScreen({super.key});
@@ -27,7 +146,10 @@ class RadarMapScreen extends ConsumerWidget {
     final region = ref.watch(regionConfigProvider);
 
     return Scaffold(
-      appBar: AppBar(title: Text(l10n.appTitle)),
+      appBar: AppBar(
+        title: Text(l10n.appTitle),
+        actions: const [_LocateAction(), _PlacesAction(), _SettingsAction()],
+      ),
       body: switch (region) {
         AsyncData(:final value) => _MapWithAttribution(region: value),
         AsyncError(:final error) => Center(
@@ -136,6 +258,11 @@ class _RegionMapState extends ConsumerState<_RegionMap> {
   void dispose() {
     _lifecycle?.dispose();
     unawaited(_overlay?.detach());
+    // The controller dies with the platform view; leaving it in the provider
+    // would let the app bar drive a dead map.
+    Future<void>.microtask(
+      () => ref.read(mapControllerProvider.notifier).detach(),
+    ).ignore();
     super.dispose();
   }
 
@@ -148,6 +275,7 @@ class _RegionMapState extends ConsumerState<_RegionMap> {
   /// bounds works on every screen size.
   Future<void> _onMapCreated(MapLibreMapController controller) async {
     _controller = controller;
+    ref.read(mapControllerProvider.notifier).attach(controller);
 
     final bounds = widget.region.bounds;
     await controller.moveCamera(
@@ -209,6 +337,10 @@ class _RegionMapState extends ConsumerState<_RegionMap> {
     return MapLibreMap(
       styleString: widget.style.styleString,
       onMapCreated: _onMapCreated,
+      // Without this the controller's cameraPosition stays null, and "save the
+      // map centre" silently saves the region default instead of what the user
+      // is actually looking at.
+      trackCameraPosition: true,
       onStyleLoadedCallback: () => unawaited(_onStyleLoaded()),
       initialCameraPosition: CameraPosition(
         target: LatLng(center.latitude, center.longitude),