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

feat: persistent AI chat with multi-session history sidebar

feat: AI Coach Mode, Fraud Explanations, Monthly Narrative — 3 new intelligence features

fix: pass full account context to Groq — AI now answers with real user data

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

Deploy to HF Space