Fix barcode 500 error, GTIN mask formatting, and add price sync

- Wrap barcode generation in try-catch to prevent 500 on invalid GTIN
- Move barcode preview above GTIN input field
- Add input mask (X XXXXXX XXXXXX) and strip non-digits before save/render
- Only render barcode when >= 8 digits present
- shopify:sync now updates price alongside inventory

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/Console/Commands/ShopifySync.php

@@ -35,6 +35,11 @@ class ShopifySync extends Command
                     continue; // not mapped yet — run shopify:map first
                 }
 
+                // Preis immer aktualisieren
+                if (! $dryRun && $size->price != $variant['price']) {
+                    $size->update(['price' => $variant['price']]);
+                }
+
                 $shopifyQty = $variant['inventory_quantity'];
                 $localQty   = ProductInventory::where('size_id', $size->id)
                     ->whereNull('out_at')