refactor: 修复代码审查发现的问题

- Bug修复: formatChangeStatus 使用实际配置而非 defaultConfig
- 统一 assembler 中所有错误抛出为 CommandError
- 提取 writeIfChanged 到 adapters/utils.ts，消除 claude-code/opencode 重复代码
- 导出 SUPPORTED_TOOLS，cli.ts update 命令复用同一工具注册表
- 提取 mapError/mapCacError 函数，支持单元测试
- 补充 claude-code 适配器测试（10 个用例）
- 补充 validateChangeName、formatChangeStatus、suggestNextStep、mapError 单元测试（18 个用例）
- 共新增 3 个测试文件，测试从 96 增至 133，全部通过

tests/adapters/claude-code.test.ts

@@ -0,0 +1,127 @@
+import { describe, it, expect, beforeEach, afterEach } from "bun:test";
+import { existsSync } from "node:fs";
+import { mkdir, rm, readFile, readdir, writeFile } from "node:fs/promises";
+import { join } from "node:path";
+import { injectClaudeCode, updateClaudeCode } from "../../src/adapters/claude-code.ts";
+
+const TMP_DIR = join(import.meta.dir, "__tmp_claude_code_test__");
+
+beforeEach(async () => {
+  await mkdir(TMP_DIR, { recursive: true });
+});
+
+afterEach(async () => {
+  await rm(TMP_DIR, { recursive: true, force: true });
+});
+
+describe("injectClaudeCode", () => {
+  it("生成 discuss、plan、build、archive 的 command 文件", async () => {
+    await injectClaudeCode(TMP_DIR);
+
+    const commands = await readdir(join(TMP_DIR, ".claude", "commands"));
+    for (const stage of ["discuss", "plan", "build", "archive"]) {
+      expect(commands).toContain(`rune-${stage}.md`);
+    }
+  });
+
+  it("生成 rune-status command 文件", async () => {
+    await injectClaudeCode(TMP_DIR);
+
+    const commands = await readdir(join(TMP_DIR, ".claude", "commands"));
+    expect(commands).toContain("rune-status.md");
+  });
+
+  it("command 文件包含 bash 命令", async () => {
+    await injectClaudeCode(TMP_DIR);
+    const content = await readFile(
+      join(TMP_DIR, ".claude", "commands", "rune-discuss.md"),
+      "utf-8",
+    );
+    expect(content).toContain("rune discuss");
+    expect(content).toContain("```bash");
+  });
+
+  it("plan/build/archive command 包含变更名称提示", async () => {
+    await injectClaudeCode(TMP_DIR);
+
+    for (const stage of ["plan", "build", "archive"]) {
+      const content = await readFile(
+        join(TMP_DIR, ".claude", "commands", `rune-${stage}.md`),
+        "utf-8",
+      );
+      expect(content).toContain("变更名");
+      expect(content).toContain("如果用户没有指定变更名称");
+    }
+  });
+
+  it("discuss command 不包含变更名称提示", async () => {
+    await injectClaudeCode(TMP_DIR);
+    const content = await readFile(
+      join(TMP_DIR, ".claude", "commands", "rune-discuss.md"),
+      "utf-8",
+    );
+    expect(content).not.toContain("如果用户没有指定变更名称");
+  });
+
+  it("重复注入时不覆盖已存在的文件", async () => {
+    await injectClaudeCode(TMP_DIR);
+    const originalContent = await readFile(
+      join(TMP_DIR, ".claude", "commands", "rune-discuss.md"),
+      "utf-8",
+    );
+
+    await injectClaudeCode(TMP_DIR);
+    const content = await readFile(
+      join(TMP_DIR, ".claude", "commands", "rune-discuss.md"),
+      "utf-8",
+    );
+    expect(content).toBe(originalContent);
+  });
+});
+
+describe("updateClaudeCode", () => {
+  it("文件不存在时创建", async () => {
+    await updateClaudeCode(TMP_DIR);
+    expect(
+      existsSync(join(TMP_DIR, ".claude", "commands", "rune-discuss.md")),
+    ).toBe(true);
+  });
+
+  it("文件存在且内容一致时不覆盖", async () => {
+    await injectClaudeCode(TMP_DIR);
+    const originalContent = await readFile(
+      join(TMP_DIR, ".claude", "commands", "rune-discuss.md"),
+      "utf-8",
+    );
+
+    await updateClaudeCode(TMP_DIR);
+    const content = await readFile(
+      join(TMP_DIR, ".claude", "commands", "rune-discuss.md"),
+      "utf-8",
+    );
+    expect(content).toBe(originalContent);
+  });
+
+  it("文件存在但内容不一致时覆盖", async () => {
+    await injectClaudeCode(TMP_DIR);
+    await writeFile(
+      join(TMP_DIR, ".claude", "commands", "rune-discuss.md"),
+      "旧内容",
+    );
+
+    await updateClaudeCode(TMP_DIR);
+    const content = await readFile(
+      join(TMP_DIR, ".claude", "commands", "rune-discuss.md"),
+      "utf-8",
+    );
+    expect(content).not.toBe("旧内容");
+    expect(content).toContain("rune discuss");
+  });
+
+  it("更新 status 命令", async () => {
+    await updateClaudeCode(TMP_DIR);
+    expect(
+      existsSync(join(TMP_DIR, ".claude", "commands", "rune-status.md")),
+    ).toBe(true);
+  });
+});