feat: gate full prediction by ai_predictions feature flag

Add a prediction box above filter results on the homepage.
Server returns the full payload only when PlanFeatures::can(
'ai_predictions') — currently plus and pro. Other tiers and
guests get a trimmed {fuel_type, predicted_direction,
tier_locked: true} response so the gate is enforced server-side.

Frontend renders a compact one-liner with the national trend
direction for trimmed responses, full card for unlocked.

Hide the Pro plan card from the pricing section (pro plan
disabled in DB pending real Stripe price ids), and only show
the bottom signup CTA when the visitor is a guest.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

app/Http/Controllers/Api/PredictionController.php

@@ -5,6 +5,7 @@ namespace App\Http\Controllers\Api;
 use App\Http\Controllers\Controller;
 use App\Http\Requests\Api\PredictionRequest;
 use App\Services\NationalFuelPredictionService;
+use App\Services\PlanFeatures;
 use Illuminate\Http\JsonResponse;
 
 class PredictionController extends Controller
@@ -20,6 +21,17 @@ class PredictionController extends Controller
 
         $result = $this->predictionService->predict($lat, $lng);
 
+        $user = $request->user();
+        $canSeeFull = $user !== null && PlanFeatures::for($user)->can('ai_predictions');
+
+        if (! $canSeeFull) {
+            return response()->json([
+                'fuel_type' => $result['fuel_type'],
+                'predicted_direction' => $result['predicted_direction'],
+                'tier_locked' => true,
+            ]);
+        }
+
         return response()->json($result);
     }
 }