Batch Export Queue
Export multiple PDFs to PNG sequentially, ZIP with subdirectories.
PDF parsing and export is done locally in your browser; files are not uploaded to any server.
Phase 2: batch queue + Worker rendering (when supported)
If OffscreenCanvas is supported, rasterization runs in a Worker to reduce UI jank; otherwise it falls back to the main thread with chunking.
Add PDFs to queue (multi-select, drag multiple times)
Queue is empty.