refactor(agent): simplify harness session repo layout

packages/agent/test/harness/session-test-utils.ts

@@ -0,0 +1,55 @@
+import { existsSync, mkdirSync, rmSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import type { AgentMessage } from "@mariozechner/pi-agent-core";
+import { afterEach } from "vitest";
+
+export function createUserMessage(text: string): AgentMessage {
+	return {
+		role: "user",
+		content: [{ type: "text", text }],
+		timestamp: Date.now(),
+	};
+}
+
+export function createAssistantMessage(text: string): AgentMessage {
+	return {
+		role: "assistant",
+		content: [{ type: "text", text }],
+		api: "anthropic-messages",
+		provider: "anthropic",
+		model: "claude-sonnet-4-5",
+		usage: {
+			input: 0,
+			output: 0,
+			cacheRead: 0,
+			cacheWrite: 0,
+			totalTokens: 0,
+			cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0, total: 0 },
+		},
+		stopReason: "stop",
+		timestamp: Date.now(),
+	};
+}
+
+const tempDirs: string[] = [];
+
+export function createTempDir(): string {
+	const dir = join(tmpdir(), `pi-agent-session-${Date.now()}-${Math.random().toString(36).slice(2)}`);
+	mkdirSync(dir, { recursive: true });
+	tempDirs.push(dir);
+	return dir;
+}
+
+export function getLatestTempDir(): string {
+	return tempDirs[tempDirs.length - 1]!;
+}
+
+afterEach(() => {
+	while (tempDirs.length > 0) {
+		const dir = tempDirs.pop()!;
+		if (existsSync(dir)) {
+			rmSync(dir, { recursive: true, force: true });
+		}
+	}
+});