Add idempotent light migrations so new columns (storage_path, etc.) apply to existing Postgres tables

Supabase Storage for raw uploaded files (gated, local fallback) + signed download endpoint

Supabase migration: Postgres engine (psycopg2) + pgvector vector store with Chroma fallback

Memory overhaul: cross-session (client_id), LLM extraction+dedup, provenance, edit endpoint

Per-browser chat isolation: scope sessions by X-Client-Id so users can't see each other's chats

Nexus Memory backend on HF Spaces (Docker + Ollama)