chore: remove rag-8000.zcodecorp.in live links and hackathon text

feat: fix image loading (LFS media URLs), improve Blog.MD tech depth, cleanup README

feat: add YouTube demo & GitHub repo links to README and Blog

Add RAG OS demo GIF, fix image rendering (sanitize_html=False), de-dup blog wording

Expand Blog.MD with HF Space story, RAG Master motivation, Agentic RAG OS origin; reorder links (RAG OS last) in README and Blog

Add Blog.MD, move plots to assets/qwen-finetuning-plots, update README badge & plot paths, update HF model card with training results