nats-broker Conformance Pack

User Stories

backend services can communicate over a shared broker for trades and market prices.
frontend can receive live account updates and pricing updates over websocket via ingress.

NATS service is reachable and healthy in state runtime.
Pricing topics (pricing.<TICKER>) are observable from websocket clients.
Publisher cadence/ratio config is exposed and valid via /health.
Trade events include non-null execution price.
Position events and REST payloads include non-null average cost basis.
Realtime position updates preserve aggregate blotter semantics (existing security rows update in place).
UI semantics for market-vs-open and value-vs-cost use deterministic marker/highlight rules.