feat: production deployment setup and hardcoded URL fixes

- Fix hardcoded localhost:8000 URLs in frontend to use relative /api/v1
  path (works with Nginx proxy in prod and VITE_API_URL in dev)
- Create production entrypoint (entrypoint.prod.sh) that runs migrations,
  seeds, and starts uvicorn with 4 workers (no --reload)
- Create comprehensive install.sh script for production deployment that
  generates secure .env, builds containers, waits for health, and
  optionally triggers initial MITRE sync
- Update docker-compose.prod.yml to use production entrypoint
- Update Dockerfile to make both entrypoints executable
- Remove init.ps1 (production will always be Linux)
- Update README with production deployment instructions

docker-compose.prod.yml

@@ -68,7 +68,7 @@ services:
         condition: service_healthy
       minio:
         condition: service_started
-    command: uvicorn app.main:app --host 0.0.0.0 --port 8000 --workers 4
+    command: sh /app/entrypoint.prod.sh
     healthcheck:
       test: ["CMD", "curl", "-f", "http://localhost:8000/health"]
       interval: 10s