Remove prediction API endpoint and integrate into stations search

Consolidate prediction functionality by merging /api/prediction endpoint into /api/stations response. Move prediction logic from PredictionController into StationController, returning prediction data alongside station results. Replace usePrediction composable with unified useStations that returns {stations, meta, prediction}. Remove PredictionRequest, related tests, and unused Vue components (FuelFinderTest, MapTest, RecommendationTest, StationListTest). Add PredictionFull component and UpsellBanner. Extend NationalFuelPredictionService to include weekly_summary (7-day series, yesterday/today averages, cheapest/priciest days) and oil signal from price_predictions table. Update Home.vue to consume prediction from stations response. Add Plan::resolveCadenceForUser helper and configure Cashier to use custom Subscription model.

app/Providers/AppServiceProvider.php

@@ -3,6 +3,7 @@
 namespace App\Providers;
 
 use App\Listeners\HandleStripeWebhook;
+use App\Models\Subscription;
 use App\Services\ApiLogger;
 use App\Services\LlmPrediction\AnthropicPredictionProvider;
 use App\Services\LlmPrediction\GeminiPredictionProvider;
@@ -14,6 +15,7 @@ use Illuminate\Support\Facades\DB;
 use Illuminate\Support\Facades\Event;
 use Illuminate\Support\ServiceProvider;
 use Illuminate\Validation\Rules\Password;
+use Laravel\Cashier\Cashier;
 use Laravel\Cashier\Events\WebhookReceived;
 
 class AppServiceProvider extends ServiceProvider
@@ -41,6 +43,8 @@ class AppServiceProvider extends ServiceProvider
     {
         $this->configureDefaults();
 
+        Cashier::useSubscriptionModel(Subscription::class);
+
         Event::listen(WebhookReceived::class, HandleStripeWebhook::class);
     }