feat: remove Documents nav + add in-app Documentation page + BANKBOT_DOCUMENTATION.txt

feat: improved light mode + language sync to html lang attribute

feat: Document Analyzer, Persistent AI Memory, Multi-language (EN/HI/MR), Dark/Light Theme

fix: resolve AI assistant page client crash by converting to HTTP streaming fallback, passing env vars to supervisord, and add payments feature

feat: login/register page, auth guard, working logout, real user identity, fraud detection UI, remove hardcoded API key

Fix: Unignore and track frontend/src/ directory in Git