test: 添加 Tool 系统单元测试 (测试计划 01)

覆盖 buildTool、toolMatchesName、findToolByName、getEmptyToolPermissionContext、
filterToolProgressMessages、parseToolPreset、parseGitCommitId、detectGitOperation
共 46 个测试用例全部通过。

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/__tests__/tools.test.ts

@@ -0,0 +1,24 @@
+import { describe, expect, test } from "bun:test";
+import { parseToolPreset } from "../tools";
+
+describe("parseToolPreset", () => {
+  test('returns "default" for "default" input', () => {
+    expect(parseToolPreset("default")).toBe("default");
+  });
+
+  test('returns "default" for "Default" input (case-insensitive)', () => {
+    expect(parseToolPreset("Default")).toBe("default");
+  });
+
+  test("returns null for unknown preset", () => {
+    expect(parseToolPreset("unknown")).toBeNull();
+  });
+
+  test("returns null for empty string", () => {
+    expect(parseToolPreset("")).toBeNull();
+  });
+
+  test("returns null for random string", () => {
+    expect(parseToolPreset("custom-preset")).toBeNull();
+  });
+});