fix: guard against undefined fields when loading old localStorage data

Old entries in localStorage lack new fields (department, role, contactPersons,
linkedEntryIds, attachments, versions, placeholders, ipAddress, vendor, model).
Add null-coalescing guards to prevent client-side crashes on property access.

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

src/modules/digital-signatures/components/digital-signatures-module.tsx

@@ -157,8 +157,8 @@ export function DigitalSignaturesModule() {
                         {asset.usageNotes && (
                           <p className="text-xs text-muted-foreground line-clamp-1">Note: {asset.usageNotes}</p>
                         )}
-                        {asset.versions.length > 0 && (
-                          <p className="text-xs text-muted-foreground">Versiuni: {asset.versions.length + 1}</p>
+                        {(asset.versions ?? []).length > 0 && (
+                          <p className="text-xs text-muted-foreground">Versiuni: {(asset.versions ?? []).length + 1}</p>
                         )}
                       </div>
                     </CardContent>

src/modules/digital-signatures/hooks/use-signatures.ts

@@ -60,7 +60,7 @@ export function useSignatures() {
     const existing = assets.find((a) => a.id === assetId);
     if (!existing) return;
     const version: AssetVersion = { id: uuid(), imageUrl, notes, createdAt: new Date().toISOString() };
-    const updatedVersions = [...existing.versions, version];
+    const updatedVersions = [...(existing.versions ?? []), version];
     await updateAsset(assetId, { imageUrl, versions: updatedVersions });
   }, [assets, updateAsset]);