docs: README.md 수정

Merge pull request #300 from chore/281-dosc-readme-update

docs: readme.md 업데이트

Merge pull request #299 from 13aek/chore/298-setting-change_env_example

chore: change env_example to Google Sheet copy-based format (RDS included)

merge: fix/#296-recommendation-logic-user-conditions-and-output -> develop

merge: chore/#294-secure-setting-activate -> develop

style: apply ruff format

fix: recomandation logic and output fix

fix: 벡터디비 설정 원복

chore: 보안 설정 활성화

merge: feat/#279-main-recommend-for-guest-and-empty-bookmark -> develop

fix: 충돌 해결

feat: 메인 추천 로직 개선 및 카테고리 기반 추천 로직 수정

style: apply ruff format