fix: harden browser file picker and remove legacy

upload/frontend/table/add_file_with_dedup.js

@@ -27,6 +27,28 @@ export function addFileWithDedup(state, fileNode) {
   const accepted = accept(fileNode);
   // Пустой ZIP/каталог не должен появляться в таблице как пустая строка.
   if (!accepted || (accepted.kind !== 'file' && !accepted.children.length)) return false;
+  if (accepted.kind !== 'file') {
+    const existing = state.nodes.find((node) => node.kind !== 'file' && node.path === accepted.path);
+    if (existing) {
+      mergeChildren(existing, accepted);
+      return true;
+    }
+  }
   state.nodes.push(accepted);
   return true;
+}
+
+function mergeChildren(target, incoming) {
+  incoming.children.forEach((child) => {
+    if (child.kind === 'file') {
+      const duplicate = target.children.some((existing) => existing.kind === 'file'
+        && existing.path === child.path && existing.file.size === child.file.size);
+      if (!duplicate) target.children.push(child);
+      return;
+    }
+    const existing = target.children.find((candidate) => candidate.kind !== 'file'
+      && candidate.path === child.path);
+    if (existing) mergeChildren(existing, child);
+    else target.children.push(child);
+  });
 }