[Feature]: add content (pdf, file, image) to the prompt for more context

### Problem Statement

It will be a good idea in addition to the prompt to add a file with logs, pdf, image to help the AI get context beyond the time series / logs in prometheus/loki

### Proposed Solution

a little button to add more context

### Use Case

get more accurate results

### Alternatives Considered

_No response_

### Feature Category

Chat Interface

### Priority

Medium - Nice to have

### Examples or Mockups

_No response_

### Implementation Ideas

_No response_

### Breaking Changes

_No response_

### Additional Context

_No response_

### Contribution

- [ ] I would like to work on this feature and submit a PR
- [ ] I can help with testing this feature
- [ ] I can help with documentation for this feature

### Pre-submission Checklist

- [x] I have searched existing issues and discussions to ensure this is not a duplicate
- [x] I have provided a clear use case for this feature
- [ ] I have considered how this feature might affect existing functionality

Start with the Chat Interface entry point and trace how prompts currently use Prometheus and Loki context. Determine how file, PDF, and image inputs should be accepted and passed to the AI, then define completion around a working add-context control and accurate prompt context without breaking existing chat behavior.

Written by the indexing model from the issue text.