test: stand up test scaffolding with bun test

- Create test/ directory with a minimal LogService test
- Prove out the pattern: bun test natively discovers and runs tests
  in the test/ directory using ESM-style imports from ../src/

test/log-service.test.ts

@@ -0,0 +1,11 @@
+import { describe, test, expect } from "bun:test";
+import { LogService } from "../src/log-service";
+
+describe("LogService", () => {
+  test("creates a root logger on construction", () => {
+    const svc = new LogService();
+
+    expect(svc.ROOT_LOGGER).toBeDefined();
+    expect(svc.ROOT_LOGGER.name).toBe("ROOT");
+  });
+});