Reverse-geocode a general area label for logged searches

Each search now stores an `area_label` (district/town) reverse-geocoded from its
coarsened ~1km lat/lng bucket via postcodes.io, surfaced in the Filament Searches
admin as a sortable/searchable column plus an area filter. Geocoding is cached 30
days per bucket, queries a 2km radius so low-density buckets still match the
default 100m miss, and fails gracefully to null. Adds `searches:backfill-areas`
(scheduled hourly) to label existing rows and retry stragglers.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/Feature/Api/StationControllerTest.php

@@ -12,6 +12,17 @@ uses(RefreshDatabase::class);
 
 beforeEach(function () {
     $this->withHeaders(['X-Api-Key' => config('app.api_secret_key')]);
+
+    // Every search reverse-geocodes its lat/lng bucket to an area label. Fake the
+    // postcodes.io reverse endpoint (query-string form) so tests never hit the
+    // network; the path form (/postcodes/SW1A1AA) used for forward lookups is
+    // matched by per-test stubs and is unaffected by this.
+    Http::fake([
+        'api.postcodes.io/postcodes?*' => Http::response([
+            'status' => 200,
+            'result' => [['admin_district' => 'Testshire']],
+        ]),
+    ]);
 });
 
 function asPaidUserOnStations(string $tier = 'plus'): User
@@ -114,6 +125,19 @@ it('logs a search record for each request', function () {
     ]);
 });
 
+it('stores the reverse-geocoded area label on the search record', function () {
+    $station = Station::factory()->create(['lat' => 52.555064, 'lng' => -0.256119]);
+    StationPriceCurrent::factory()->create(['station_id' => $station->node_id, 'fuel_type' => FuelType::B7Standard, 'price_pence' => 14500]);
+
+    $this->getJson('/api/stations?lat=52.555064&lng=-0.256119&fuel_type=b7_standard&radius=10');
+
+    $this->assertDatabaseHas('searches', [
+        'lat_bucket' => '52.56',
+        'lng_bucket' => '-0.26',
+        'area_label' => 'Testshire',
+    ]);
+});
+
 it('returns 422 when required params are missing', function () {
     $this->getJson('/api/stations?lat=52.5')
         ->assertUnprocessable();