fix: copy button uses plain number format (nr. 42 din 11.03.2026)

Strips company prefix and leading zeros from registry number.

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

src/modules/registratura/components/registry-table.tsx

@@ -524,7 +524,9 @@ function CopyNumberButton({ entry }: { entry: RegistryEntry }) {
 
   const handleCopy = (e: React.MouseEvent) => {
     e.stopPropagation();
-    const text = `nr. ${entry.number} din ${formatDate(entry.date)}`;
+    // Extract plain number: "BTG-0042/2026" → "42", "US-0123/2026" → "123"
+    const plain = entry.number.replace(/^[A-Z]+-0*/, "").replace(/\/.*$/, "");
+    const text = `nr. ${plain} din ${formatDate(entry.date)}`;
     void navigator.clipboard.writeText(text).then(() => {
       setCopied(true);
       setTimeout(() => setCopied(false), 1500);