test: Phase 1 — 添加 8 个纯函数测试文件 (+134 tests)

- errors.test.ts: 28 tests (isAbortError, toError, errorMessage, getErrnoCode, isFsInaccessible, classifyAxiosError 等)
- shellRuleMatching.test.ts: 22 tests (permissionRuleExtractPrefix, hasWildcards, matchWildcardPattern, parsePermissionRule 等)
- argumentSubstitution.test.ts: 18 tests (parseArguments, parseArgumentNames, generateProgressiveArgumentHint, substituteArguments)
- CircularBuffer.test.ts: 12 tests (add, addAll, getRecent, toArray, clear, length)
- sanitization.test.ts: 14 tests (partiallySanitizeUnicode, recursivelySanitizeUnicode)
- slashCommandParsing.test.ts: 8 tests (parseSlashCommand)
- contentArray.test.ts: 6 tests (insertBlockAfterToolResults)
- objectGroupBy.test.ts: 5 tests (objectGroupBy)

总计：781 tests / 40 files

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

src/utils/__tests__/objectGroupBy.test.ts

@@ -0,0 +1,41 @@
+import { describe, expect, test } from "bun:test";
+import { objectGroupBy } from "../objectGroupBy";
+
+describe("objectGroupBy", () => {
+  test("groups items by key", () => {
+    const result = objectGroupBy([1, 2, 3, 4], (n) =>
+      n % 2 === 0 ? "even" : "odd"
+    );
+    expect(result.even).toEqual([2, 4]);
+    expect(result.odd).toEqual([1, 3]);
+  });
+
+  test("returns empty object for empty input", () => {
+    const result = objectGroupBy([], () => "key");
+    expect(Object.keys(result)).toHaveLength(0);
+  });
+
+  test("handles single group", () => {
+    const result = objectGroupBy(["a", "b", "c"], () => "all");
+    expect(result.all).toEqual(["a", "b", "c"]);
+  });
+
+  test("passes index to keySelector", () => {
+    const result = objectGroupBy(["a", "b", "c", "d"], (_, i) =>
+      i < 2 ? "first" : "second"
+    );
+    expect(result.first).toEqual(["a", "b"]);
+    expect(result.second).toEqual(["c", "d"]);
+  });
+
+  test("works with objects", () => {
+    const items = [
+      { name: "Alice", role: "admin" },
+      { name: "Bob", role: "user" },
+      { name: "Charlie", role: "admin" },
+    ];
+    const result = objectGroupBy(items, (item) => item.role);
+    expect(result.admin).toHaveLength(2);
+    expect(result.user).toHaveLength(1);
+  });
+});