feat: add XTTSv2 TTS endpoint + public demo chat with Amber voice, template-first responses, and Chronos memory consent storage

Force Docker cache bust v9 + add startup version marker to confirm new code

Diag: Add verbose logging and debug uvicorn CMD for HF deployment

Migrate Backend to Hugging Face Spaces (16GB RAM optimization)

Migrate: SQLite+ChromaDB → Neon PostgreSQL+pgvector (persistent cloud storage)

Deploy: Add Render.yaml blueprint and dynamic PORT for cloud deployment

Update Dockerfile port for Hugging Face Spaces deployment

Initial commit for Chronos OS MVP