feat(ai): design improvements for chat popup, speeddial menu, resizable answer card, and centered header disclaimer

fix: menu button safe-area inset top for iOS PWA black-translucent

feat: normalize reference extraction and popup UI

feat: migrate jina v5, refine AI popup, add reference popup UI

feat: mobile bottom nav bar with auto-hide + page jump

feat: keyboard + swipe navigation; fix: FastAPI 0.136.1 for Starlette 1.0.0

Deploy React+FastAPI webapp to HF Space