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__/slashCommandParsing.test.ts

@@ -0,0 +1,58 @@
+import { describe, expect, test } from "bun:test";
+import { parseSlashCommand } from "../slashCommandParsing";
+
+describe("parseSlashCommand", () => {
+  test("parses simple command", () => {
+    const result = parseSlashCommand("/search foo bar");
+    expect(result).toEqual({
+      commandName: "search",
+      args: "foo bar",
+      isMcp: false,
+    });
+  });
+
+  test("parses command without args", () => {
+    const result = parseSlashCommand("/help");
+    expect(result).toEqual({
+      commandName: "help",
+      args: "",
+      isMcp: false,
+    });
+  });
+
+  test("parses MCP command", () => {
+    const result = parseSlashCommand("/tool (MCP) arg1 arg2");
+    expect(result).toEqual({
+      commandName: "tool (MCP)",
+      args: "arg1 arg2",
+      isMcp: true,
+    });
+  });
+
+  test("parses MCP command without args", () => {
+    const result = parseSlashCommand("/tool (MCP)");
+    expect(result).toEqual({
+      commandName: "tool (MCP)",
+      args: "",
+      isMcp: true,
+    });
+  });
+
+  test("returns null for non-slash input", () => {
+    expect(parseSlashCommand("hello")).toBeNull();
+  });
+
+  test("returns null for empty string", () => {
+    expect(parseSlashCommand("")).toBeNull();
+  });
+
+  test("returns null for just slash", () => {
+    expect(parseSlashCommand("/")).toBeNull();
+  });
+
+  test("trims whitespace before parsing", () => {
+    const result = parseSlashCommand("  /search foo  ");
+    expect(result!.commandName).toBe("search");
+    expect(result!.args).toBe("foo");
+  });
+});