- Add MinerU PDF parser support via external API or local installation
- Configure MinerU through environment variables (MINERU_APISERVER, etc.)
- Add per-dataset MinerU settings: language, formula/table recognition
- Add MinerU config form fields in Knowledge Base settings
- Remove MinerU from LLM factories (not a typical LLM model)
- Clean up unused ingestors tab from settings
### What problem does this PR solve?
Treat MinerU as an OCR model.
### Type of change
- [x] New Feature (non-breaking change which adds functionality)
- [x] Refactoring