docs: update README and docs with new scrapers and location filter fixes

feat: dark mode docs + add credits and citation to README

fix: add .nojekyll to disable Jekyll on GitHub Pages

docs: add PhD eligibility gate section + clean README

docs: update HTML and README for new agent/ folder structure

docs: replace MkDocs with single-file macOS-styled HTML

fix: remove deprecated Groq models (gemma2-9b-it, mixtral-8x7b-32768)

feat: remove DuckDuckGo scraper and 'any' position type; add docs link to README

docs: add full MkDocs Material documentation site