- New UserManager service with HTTPS auth, credential sync, traffic tracking, and kick API
- Integrates into all 10 protocol inbounds (hysteria2, tuic, vless, vmess, trojan,
shadowsocks, http, socks, mixed, naive)
- Each inbound auto-detects user_manager from service context, falls back to static config
- Auth server contract: POST /api/auth, GET /api/credentials, POST /api/traffic
