feat: enable RAG and Agent on HF Spaces via OpenAI API key

feat: per-user OpenAI key + model preferences persisted in DB

feat: add OpenAI API support (gpt-5.4 family) alongside Ollama

fix: reduce compliance variability with temperature=0 and larger context

fix: bypass LLM tool-call for compliance requests to ensure reliability

fix: stabilize ENFSI compliance tool streaming and PDF rendering

feat: add Conformità ENFSI as agent tool with inline report and PDF download

fix: render NER table correctly in agent chat

fix: agent session isolation, audit rollback, persistent images, legacy endpoint

fix: isolate agent temp files per session + fix PaddlePaddle PIR on Windows

feat: inject project context into agent system prompt

feat: show extracted signature image inline in agent chat

feat: separate LLM and VLM model slots + fix agent OCR model routing

feat: Agente Documentale LangChain + OCR selector + stop + SQLite WAL

feat: ENFSI compliance checker + sidebar model selector

fix: RAG chat fully functional in FastAPI backend

feat: replace ultralytics/YOLOv8 with Conditional DETR (Apache 2.0)

feat: include Step 7 LLM synthesis in final pipeline report

feat: extract AI logic into shared core/ package (Phase 0)