This allow a prompt to feed the LLM with the title as determined by
Paperless to improve its suggestion.
This also fixes the case when `getSuggestedTags` or
`getSuggestedCorrespondent` are called, but `GenerateTitles` is off (in
which case an empty title was used).
Fixes#137
## Summary by CodeRabbit
- **New Features**
- Updated environment variable descriptions for improved clarity on OCR processing options.
- Enhanced the `doOCRViaLLM` method to support different LLM providers and improve image data handling.
- **Bug Fixes**
- Standardized error handling for better reporting across multiple methods.
- **Documentation**
- Revised Docker Compose section in `README.md` to reflect updated environment variable options.
