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: production readiness, security, performance, and worker refactoring

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

fix: implement local_session context manager inside tasks.py to prevent event loop mismatch errors

Initialize Archvise API backend for Hugging Face Spaces