Reduce Transfer storage price to GHS 0.15 per GB per month.

Updates config default, env examples, and removes hardcoded GHS 1.00 copy on the dashboard.

Co-authored-by: Cursor <cursoragent@cursor.com>

app/Models/Transfer.php

@@ -79,6 +79,6 @@ class Transfer extends Model
 
     public function monthlyCostGhs(): float
     {
-        return round($this->storageGb() * (float) config('transfer.price_per_gb_month', 1.0), 2);
+        return round($this->storageGb() * (float) config('transfer.price_per_gb_month', 0.15), 2);
     }
 }