feat(config): support OPENROUTER_API_KEY, GROQ_API_KEY, and GEMINI_API_KEY loaded from .env

fix: add fallback defaults to Settings and fix limiter import in auth router

fix: resolution of critical blockers (P0/P1/P2 fixes) - async Redis, atomic credit updates, schema compatibility, task event loop safety, rate limits, timezone datetimes

fix: all 9 production audit issues - DEBUG default, delete_account commit, guest session security, GitHub OAuth redirect, unlimited credits sentinel

fix: production readiness, security, performance, and worker refactoring

Implement OpenRouter API integration and Redis event caching/replay to fix stuck streams on tab switch

feat: replace Firebase with Supabase JWT auth (ES256/JWKS + HS256 fallback)

Initialize Archvise API backend for Hugging Face Spaces