Integrate DeBERTa-v3 PII guardrail, rename guardrail modules, fix ModelResponse item assignment error, and display guardrailed query in Streamlit UI

feat: integrate Streamlit frontend dashboard, configure dynamic proxy URL, and support core security guardrails

feat: upgrade PII guardrail to a scalable configuration-driven engine with live UI status badges

feat: implement complexity-aware routing, visual playground UI enhancements, and reversible PII anonymization engine

Initial commit: class-based LiteLLM load balancer proxy with PII shielding and cost-aware routing