Commercial launch: Postgres auth, BTCPay payments, premium UI

- Postgres: users, api_keys, usage_log, payments tables
- Auth: API key system with rate limiting (402 when out of calls)
- BTCPay:  Bitcoin = 5 API calls, webhook for auto-credit
- Admin: sk-admin-unlimited-2026 with unlimited calls
- UI: Landing, Pricing (/5calls), Signup (no KYC), Dashboard with usage stats
- Footer: Created by drjones + Buy Me a Coffee link
- All endpoints auth-gated except signup, status, pages

Dockerfile

@@ -2,7 +2,7 @@ FROM python:3.11-slim
 
 WORKDIR /app
 
-RUN pip install --no-cache-dir fastapi uvicorn httpx python-dotenv
+RUN pip install --no-cache-dir fastapi uvicorn httpx python-dotenv psycopg2-binary
 
 COPY backend.py .