refactor: remove global RateCardProfile singleton usage from controllers and delete unused welcome view

app/Models/InvoiceSettings.php

@@ -35,25 +35,39 @@ class InvoiceSettings extends Model
         'default_tax_rate' => 'decimal:2',
     ];
 
+    protected static ?self $instance = null;
+
     /** Always return the single settings row, creating it if absent. */
     public static function instance(): self
     {
-        return static::firstOrCreate([], [
+        if (self::$instance) {
+            return self::$instance;
+        }
+
+        self::$instance = static::firstOrCreate([], [
             'invoice_prefix' => 'INV',
             'invoice_next_number' => 1,
             'accent_color' => '#FFB7C5',
             'default_tax_rate' => 2.5,
             'default_currency' => 'IDR',
         ]);
+
+        return self::$instance;
+    }
+
+    protected static function booted()
+    {
+        static::saved(fn ($model) => self::$instance = $model);
+        static::deleted(fn () => self::$instance = null);
     }
 
-    /** Generate the next invoice number and increment the counter. */
     public static function generateNumber(): string
     {
         $settings = static::instance();
         $prefix = rtrim($settings->invoice_prefix, '-');
         $number = str_pad((string) $settings->invoice_next_number, 3, '0', STR_PAD_LEFT);
         $settings->increment('invoice_next_number');
+        \Illuminate\Support\Facades\Cache::forget('invoice_settings');
         return $prefix . '-' . $number;
     }
 }