Upload page: append sequential drag-and-drop files and make document removal easier to find

[nonprofittechy]

Partner testing feedback

Vermont LITEFile testing on a laptop in Chrome:

• @VTskier Dragging PDFs into the upload area one at a time did not accumulate the files. The tester had to drag all documents together to get more than one document selected. Users are likely to drag documents one at a time.
• @VTskier The tester accidentally uploaded the affidavit twice and did not see where to delete the extra copy.

Code check / feasibility

This is actionable in the LITEFile front end.

efile_app/efile/static/js/upload-documents.js currently creates a new DataTransfer inside setFiles(files) and assigns only the files from the latest selection/drop to input.files. A later drop therefore replaces the earlier pending selection rather than appending to it.

Current main does have uploaded-document removal: upload_documents.html renders a trash-icon button and upload-documents.js sends the remove action. That means the second report is primarily a discoverability problem (and may also reflect the deployed version tested). Related historical issue: #42.

Proposed behavior

• A second and later drag/drop should append files to the current pending selection rather than replace them.
• Avoid adding an exact duplicate pending file when practical (for example, matching name/size/last-modified metadata), or otherwise make duplicates obvious before upload.
• Show the pending file names before upload, with a visible way to remove one before submitting.
• Make the removal action for already-uploaded documents more discoverable than an unlabeled trash icon alone (for example, visible Remove text on wider viewports while retaining the accessible label/icon).
• Add a browser/unit test covering two sequential drops and removal.

Acceptance criteria

1. Drop PDF A, then PDF B: both are selected for upload.
2. A user can remove either pending file before uploading.
3. After upload, each document has an obvious removal action.
4. Existing multi-file selection/drop still works.

[VTskier]

To clarify:

This happened during the initial document upload: Dragging PDFs into the upload area one at a time did not accumulate the files. The tester had to drag all documents together to get more than one document selected. Users are likely to drag documents one at a time.

This happened when uploading additional documents:
The tester accidentally uploaded the affidavit twice and did not see where to delete the extra copy.