feat(GOV-009): 建立后端契约与健康检查

server/libs/infrastructure/src/message-bus.adapter.ts

@@ -0,0 +1,11 @@
+import type { MessageEnvelope } from '../../message-contracts/src/message-envelope';
+
+export type MessageHandler<TPayload = unknown> = (
+  message: Readonly<MessageEnvelope<TPayload>>,
+) => Promise<void>;
+
+export interface MessageBusAdapter {
+  publish<TPayload>(message: Readonly<MessageEnvelope<TPayload>>): Promise<void>;
+  subscribe<TPayload>(eventType: string, handler: MessageHandler<TPayload>): Promise<void>;
+  close(): Promise<void>;
+}