refactor(root): trim first 10 lines from README.md content in root endpoint

style(main): update syntax highlighting style to default

feat(api): enhance root endpoint with markdown rendering

refactor(api): simplify root endpoint and remove markdown rendering

style(main): improve HTML response formatting in error handling

refactor(main): switch markdown conversion library and update dependencies

feat(root): display README as HTML on root endpoint

refactor(main): improve code structure and error handling

feat(auth): add public endpoint handling in auth middleware

refactor(auth): replace custom AuthMiddleware with FastAPI middleware decorator

feat(auth): implement token-based authentication middleware

feat(auth): implement token-based authentication middleware

refactor(main): replace '/ping' endpoint with root endpoint

chore(docker): set default user to non-root in Dockerfile