[FEATURE REQUEST] Implement Support for Bedrock Citations API

## Overview
Amazon Bedrock recently released the Citations API for Claude models, which enables the reading and analysis of multiple PDF and Excel files. Implementing support for this feature in Bedrock Engineer would greatly enhance its capabilities and meet the high demand from our users for multi-document analysis.

## Proposed Feature
Integrate Amazon Bedrock's Citations API to enable Bedrock Engineer to read and analyze multiple PDF and Excel files.

## Requirements
- Implement file upload functionality for multiple PDFs and Excel files
- Integrate with Amazon Bedrock's Citations API for Claude models
- Develop a user interface for displaying citation information and source documents
- Enable users to interact with the analyzed content, ask questions, and receive cited responses
- Implement error handling and progress indicators for file processing

## Potential Implementation
1. Add a new section in the UI for document upload and analysis
2. Utilize Amazon Bedrock's Citations API to process uploaded files
3. Develop a citation display system to show source information alongside AI responses
4. Integrate with existing chat interface for user interactions with the analyzed documents

## Benefits
- Enhance Bedrock Engineer's document analysis capabilities
- Provide users with the ability to analyze multiple documents simultaneously
- Improve the accuracy and traceability of AI-generated responses through citations
- Meet the growing demand for multi-document analysis in various industries

## Next Steps
- Review Amazon Bedrock's Citations API documentation and requirements
- Design UI mockups for the document upload and citation display features
- Estimate development time and resources required
- Prioritize this feature in our development roadmap

Please provide any feedback or additional requirements for this feature.