Fix auto-registration of tasks, add offline DB fallback for local evaluation, and improve rate-limit out-of-credit failover

feat(security): implement Security & Vulnerability Audit Suite (Tests 6-14) with Gradio UI and BYO file upload safeguards

feat: per-provider cooldown tracking, tightened reward ceilings, and failover enhancements

Create isolated db_session per test and include 404 in immediate failover rotation

Catch APIConnectionError and APITimeoutError in failover retry loop

Add backup provider keys to Settings in config.py and diagnostic logging in next_provider

Fix provider failover tier ordering and fix list tolist attribute error in embed_state

Version-1