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/Http/Controllers/Api/AuthController.php

@@ -63,10 +63,19 @@ class AuthController extends Controller
     public function me(Request $request): JsonResponse
     {
         $user = $request->user();
+        $subscription = $user->subscription();
+
+        $expiresAt = $subscription?->ends_at ?? $subscription?->current_period_end;
 
         return response()->json(array_merge(
             $user->toArray(),
-            ['tier' => Plan::resolveForUser($user)->name],
+            [
+                'tier' => Plan::resolveForUser($user)->name,
+                'subscription_cancelled' => $subscription?->canceled() ?? false,
+                'subscription_cadence' => Plan::resolveCadenceForUser($user),
+                'subscribed_at' => $subscription?->created_at?->toIso8601String(),
+                'subscription_expires_at' => $expiresAt?->toIso8601String(),
+            ],
         ));
     }
 }