refactor(agent): run harness loop directly

packages/agent/vitest.harness.config.ts

@@ -0,0 +1,18 @@
+import { defineConfig } from "vitest/config";
+
+export default defineConfig({
+	test: {
+		globals: true,
+		environment: "node",
+		testTimeout: 30000,
+		include: ["test/harness/**/*.test.ts"],
+		coverage: {
+			provider: "v8",
+			all: true,
+			include: ["src/harness/**/*.ts", "src/agent.ts", "src/agent-loop.ts"],
+			exclude: ["src/**/*.d.ts"],
+			reporter: ["text", "html", "lcov"],
+			reportsDirectory: "coverage/harness",
+		},
+	},
+});