Optimize folder upload by creating folders at the same depth level in
parallel and uploading all files concurrently. This reduces upload time
from O(n) sequential requests to O(depth) folder requests + 1 file request.
Split use-file-operations.ts (248 lines) into smaller focused hooks:
- use-create-operations.ts for file/folder creation and upload
- use-modify-operations.ts for rename and delete operations
- use-file-operations.ts now serves as orchestrator maintaining backward compatibility
Extract TreeNodeIcon component from tree-node.tsx for cleaner separation of concerns.
Add brief comments to drag hooks explaining their purpose and relationships.
