Feature Request: Support for Multiple Document Upload and Search

[JingleiTAO]

Currently, the demo supports uploading and searching within a single document. We propose adding support for multiple document uploads so that users can search across several documents at once.

Features:

1. Multiple Document Upload: Allow users to upload multiple files (PDF, DOCX, etc.) simultaneously.
2. Cross-Document Search: Enable searching across all uploaded documents.
3. Display Results: Show results from multiple documents with clear identification of the source document.
4. Document Management: Allow easy management (labeling, deleting) of uploaded documents.

Benefits:

1. Users can query multiple documents at once, improving the search experience.
2. Ideal for users dealing with multiple related documents (e.g., technical papers, contracts).

Technical Considerations:

1. Document indexing for efficient search across multiple files.
2. UI changes to handle multiple document uploads and search results display.