fix: capture all formData entries in share targets; bump sw cache to v4

src/app/share/route.ts

@@ -169,13 +169,9 @@ export async function POST(req: NextRequest) {
       ).trim();
       url = ((formData.get('url') as string) || '').trim();
 
-      const rawFiles = [
-        ...formData.getAll('files'),
-        ...formData.getAll('file'),
-      ];
-      for (const item of rawFiles) {
-        if (item && typeof item === 'object' && 'arrayBuffer' in item) {
-          const file = item as File;
+      for (const [key, value] of formData.entries()) {
+        if (value && typeof value === 'object' && 'arrayBuffer' in value) {
+          const file = value as File;
           if (file.size > 0) {
             uploadedFiles.push(file);
           }