feat(todo): the server finds places through the instance's Photon (ADR 0033, D32)

Todo's locations search through the person's own instance, as Train's
planner does, not a public service: `SearchEndpoint` on `PlaceSearch`, for
those signed in, 60 searches a minute, nothing kept or logged. Its `Place`
carries the address's parts and the object in OpenStreetMap, and a shop's
car park or charger is left out, which came first for `Lindau EDEKA`.

`compose.todo-search.yaml` puts Todo's server on compose.search.yaml's
Photon. A file of its own: without it Todo starts as it did, and offers no
search.

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_server/test/integration/search/search_endpoint_test.dart

@@ -0,0 +1,190 @@
+import 'package:clock/clock.dart';
+import 'package:halkyon_todo_server/src/generated/protocol.dart';
+import 'package:halkyon_todo_server/src/search/photon.dart';
+import 'package:halkyon_todo_server/src/search/place_search.dart';
+import 'package:serverpod/serverpod.dart';
+import 'package:test/test.dart';
+
+import '../../unit/search/photon_test.dart' show photonAnswer;
+import '../test_tools/serverpod_test_tools.dart';
+
+/// Photon as the tests want it: what it answers, and what it was asked.
+class _FakePhoton implements PlaceFinder {
+  final asked = <({String query, PlacePoint? near, String? language})>[];
+  final limits = <int>[];
+  bool failing = false;
+
+  /// What Photon finds.
+  List<Map<String, Object?>> answer = const [
+    {
+      'lat': 52.47,
+      'lon': 13.4,
+      'name': 'Tempelhofer Feld',
+      'type': 'other',
+      'city': 'Berlin',
+      'country': 'Germany',
+    },
+  ];
+
+  @override
+  Future<Map<String, Object?>> search(
+    String query, {
+    PlacePoint? near,
+    String? language,
+    required int limit,
+  }) async {
+    asked.add((query: query, near: near, language: language));
+    limits.add(limit);
+    if (failing) {
+      throw const PhotonFailed('down');
+    }
+    return photonAnswer(answer);
+  }
+}
+
+Matcher _refused(String reason) =>
+    throwsA(isA<SearchRefused>().having((r) => r.reason, 'reason', reason));
+
+/// Places found by the instance's Photon (ADR 0033, D32): for the people
+/// signed in, where the instance has one, within a limit a minute.
+void main() {
+  withServerpod('Searching for places', (sessionBuilder, endpoints) {
+    late _FakePhoton photon;
+    final alice = sessionBuilder.copyWith(
+      authentication: AuthenticationOverride.authenticationInfo(
+        const Uuid().v7(),
+        {},
+      ),
+    );
+    final bob = sessionBuilder.copyWith(
+      authentication: AuthenticationOverride.authenticationInfo(
+        const Uuid().v7(),
+        {},
+      ),
+    );
+
+    void useSearch(PlaceSearch search) =>
+        PlaceSearch.use(sessionBuilder.build().serverpod, search);
+
+    setUp(() {
+      photon = _FakePhoton();
+      useSearch(PlaceSearch(finder: photon));
+    });
+
+    test('finds places for someone signed in, nearest the map first, in '
+        'their language', () async {
+      expect(await endpoints.search.offered(alice), isTrue);
+      final places = await endpoints.search.places(
+        alice,
+        '  Tempelhof ',
+        near: PlacePoint(lat: 52.5, lon: 13.4),
+        language: 'de',
+      );
+
+      expect(places.single.name, 'Tempelhofer Feld');
+      expect(places.single.detail, 'Berlin, Germany');
+      final asked = photon.asked.single;
+      expect(asked.query, 'Tempelhof');
+      expect(asked.near?.lat, 52.5);
+      expect(asked.language, 'de');
+    });
+
+    test('a language Photon has no names in asks for none', () async {
+      await endpoints.search.places(alice, 'Paris', language: 'fr');
+      expect(photon.asked.single.language, isNull);
+    });
+
+    test('searches nothing for nobody signed in', () async {
+      final nobody = sessionBuilder.copyWith(
+        authentication: AuthenticationOverride.unauthenticated(),
+      );
+      await expectLater(
+        endpoints.search.places(nobody, 'Berlin'),
+        throwsA(isA<ServerpodUnauthenticatedException>()),
+      );
+      await expectLater(
+        endpoints.search.offered(nobody),
+        throwsA(isA<ServerpodUnauthenticatedException>()),
+      );
+      expect(photon.asked, isEmpty);
+    });
+
+    test('refuses every search where the instance has no Photon', () async {
+      useSearch(PlaceSearch());
+      expect(await endpoints.search.offered(alice), isFalse);
+      await expectLater(
+        endpoints.search.places(alice, 'Berlin'),
+        _refused('off'),
+      );
+    });
+
+    test('refuses a query too short or too long, or a point off the earth, '
+        'asking Photon nothing', () async {
+      for (final query in ['', ' x ', 'x' * (PlaceSearch.maxQuery + 1)]) {
+        await expectLater(
+          endpoints.search.places(alice, query),
+          _refused('invalid'),
+          reason: query,
+        );
+      }
+      await expectLater(
+        endpoints.search.places(
+          alice,
+          'Berlin',
+          near: PlacePoint(lat: 91, lon: 0),
+        ),
+        _refused('invalid'),
+      );
+      expect(photon.asked, isEmpty);
+    });
+
+    test('refuses a person beyond the limit a minute, not others, and '
+        'takes them again a minute later', () async {
+      final start = DateTime.utc(2026, 10, 29, 12);
+      await withClock(Clock.fixed(start), () async {
+        for (var i = 0; i < PlaceSearch.perMinute; i++) {
+          await endpoints.search.places(alice, 'Berlin');
+        }
+        await expectLater(
+          endpoints.search.places(alice, 'Berlin'),
+          _refused('tooOften'),
+        );
+        await endpoints.search.places(bob, 'Berlin');
+      });
+      await withClock(
+        Clock.fixed(start.add(const Duration(minutes: 1))),
+        () => endpoints.search.places(alice, 'Berlin'),
+      );
+    });
+
+    test('asks Photon for more than it lists, as what is no place to go is '
+        'left out, and lists no more than the limit', () async {
+      photon.answer = [
+        for (var i = 0; i < 4; i++)
+          {
+            'lat': 1,
+            'lon': 2,
+            'name': 'EDEKA',
+            'type': 'other',
+            'osm_value': 'parking',
+          },
+        for (var i = 0; i < PlaceSearch.limit + 2; i++)
+          {'lat': 1, 'lon': 2, 'name': 'EDEKA $i', 'type': 'house'},
+      ];
+
+      final places = await endpoints.search.places(alice, 'EDEKA');
+
+      expect(photon.limits.single, greaterThan(PlaceSearch.limit));
+      expect(places, hasLength(PlaceSearch.limit));
+      expect(places.first.name, 'EDEKA 0');
+    });
+
+    test("says Photon didn't answer where it fails", () async {
+      photon.failing = true;
+      await expectLater(
+        endpoints.search.places(alice, 'Berlin'),
+        _refused('unreachable'),
+      );
+    });
+  });
+}