test: add unit tests for core modules (#35)

Cover high-priority untested modules:
- util: base32, result, refs-field, storage-root, log-tag
- util-agent: storage (normalizeWorkflowConfig, resolveStorageRoot), run (parseArgv)
- agent-builtin: tools (read-file, write-file, run-command), session, detail

627 → 719 tests (+92), all passing.

Refs #35

packages/agent-builtin/__tests__/detail.test.ts

@@ -0,0 +1,49 @@
+import { mkdtemp, rm } from "node:fs/promises";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import { afterEach, beforeEach, describe, expect, test } from "vitest";
+import { createMemoryStore } from "@ocas/core";
+import { storeBuiltinDetail } from "../src/detail.js";
+import { appendSessionTurn, initSessionDir } from "../src/session.js";
+import type { BuiltinTurnPayload } from "../src/types.js";
+
+describe("storeBuiltinDetail", () => {
+  let storageRoot: string;
+
+  beforeEach(async () => {
+    storageRoot = await mkdtemp(join(tmpdir(), "builtin-detail-storage-"));
+  });
+
+  afterEach(async () => {
+    await rm(storageRoot, { recursive: true, force: true });
+  });
+
+  const makeTurn = (role: "assistant" | "tool", content: string): BuiltinTurnPayload => ({
+    role,
+    content,
+    toolCalls: null,
+    reasoning: null,
+  });
+
+  test("stores detail with turns, returns hash and turnCount", async () => {
+    const store = createMemoryStore();
+    await initSessionDir(storageRoot);
+    const sid = "detail-test";
+    await appendSessionTurn(storageRoot, sid, makeTurn("tool", "question"));
+    await appendSessionTurn(storageRoot, sid, makeTurn("assistant", "answer"));
+
+    const result = await storeBuiltinDetail(store, storageRoot, sid, "test-model", 1000, 2000);
+    expect(result.turnCount).toBe(2);
+    expect(typeof result.detailHash).toBe("string");
+    expect(result.detailHash.length).toBeGreaterThan(0);
+  });
+
+  test("empty session returns turnCount 0", async () => {
+    const store = createMemoryStore();
+    const sid = "empty-session";
+
+    const result = await storeBuiltinDetail(store, storageRoot, sid, "test-model", 1000, 2000);
+    expect(result.turnCount).toBe(0);
+    expect(typeof result.detailHash).toBe("string");
+  });
+});