UPSTREAM_BASE_URL=http://api.tsbys.com/v1
UPSTREAM_API_KEY=replace-with-your-real-key
UPSTREAM_MODEL=qwen3-max
UPSTREAM_API_STYLE=chat

# Optional fallback
FALLBACK_UPSTREAM_BASE_URL=https://dash.classicriver.cn/v1
FALLBACK_UPSTREAM_API_KEY=
FALLBACK_UPSTREAM_MODEL=gpt-5.4
FALLBACK_UPSTREAM_API_STYLE=chat

# Optional runtime tuning
CORS_ORIGIN=*
APP_TOKEN=
UPSTREAM_TIMEOUT_MS=45000
SYNTHETIC_STREAM_DELAY_MS=10
