Full text/PDF/OCR ingest into its OWN corpus with off/recursive/semantic chunking and a live chunk-boundary preview, then reranked vector search (over-fetch topK×3 → a real cross-encoder from the transformers ONNX group or the wllama GGUF group; raw + rerank scores preserved, never fabricated) with category facets and preset or corpus-calibrated similarity thresholds — carrying the core-pipeline ⇄ LangChain engine toggle. Over the promoted useKnowledgeBase engine layer; ships justified block-local ingest-panel + search-panel siblings. Nothing downloads until an explicit action. Split from ui/blocks/knowledge-base (Ingest + Search tabs; absorbs pdf-search + ocr-scanner).