fix: add missing .js extensions to imports in context.ts

Fix ESM import paths by adding required .js extensions:
- packages/worker/src/__tests__/context.ts imports

This addresses linting feedback from code review.

Co-authored-by: btravers <3476441+btravers@users.noreply.github.com>

Author: Copilot

packages/worker/src/__tests__/context.ts

@@ -1,6 +1,6 @@
 import type { ContractDefinition } from "@amqp-contract/contract";
-import { TypedAmqpWorker } from "../worker";
-import type { WorkerInferConsumerHandlers } from "../types";
+import { TypedAmqpWorker } from "../worker.js";
+import type { WorkerInferConsumerHandlers } from "../types.js";
 import { it as baseIt } from "@amqp-contract/testing/extension";
 
 export const it = baseIt.extend<{