fix: reduce example questions to 6 for cleaner 3x2 layout

fix: show all 15 example questions on one page

feat: expand example questions to 15

feat: add example questions, tighten grounding instruction, disable markdown tables

fix: move answer import after chroma_db download to prevent empty collection

refactor: switch to Groq, prep app for HF Spaces, clean up comments

Created the front end UI and the README.