chore(backlog): 记录 f05 完成

.ua/backlog.json

@@ -354,7 +354,7 @@
       "title": "ua index 幂等化：generatedAt 仅内容变化时更新",
       "motivation": "ua index 每次重写 .ua/index.json 的 generatedAt，npm run check 必然弄脏工作区，与「提交前 check」工作流冲突",
       "acceptance": "index 命令改为：若除 generatedAt 外内容与现有文件一致则不写入（或 generatedAt 改为内容哈希派生）；连续两次 npm run check 后 git status 必须干净",
-      "status": "open",
+      "status": "done",
       "notes": "来源：审计应修 #5"
     },
     {

.ua/iterations.log

@@ -43,3 +43,4 @@
 {"ts":"2026-10-23T18:44:08+08:00","id":"f02","result":"done","commit":"f2fc286","summary":"AGENTS.md 与 ITERATION.md 的 npm run check 描述补上 verify，与实际六步链一致"}
 {"ts":"2026-10-23T18:46:55+08:00","id":"f03","result":"done","commit":"f57da4c","summary":"ua 新增 lint-iterations 子命令校验留痕格式并并入 check 链，36 条历史违规行按 git author date 回填修复"}
 {"ts":"2026-10-23T18:48:36+08:00","id":"f04","result":"done","commit":"99ce0cd","summary":"commit-lint 收严：非 iter type 必须带 scope，裸 chore:/docs:/iter: 反向用例全部拒绝，COMMITTING.md 同步"}
+{"ts":"2026-10-23T18:52:12+08:00","id":"f05","result":"done","commit":"265060f","summary":"ua index 幂等化：剔除 generatedAt 比对且行尾归一化，内容无变化跳写，连续两次 check 后工作区干净"}

packages/tools/cli/bin/ua.js

@@ -56,6 +56,13 @@ function collectManifests() {
   return out;
 }
 
+/*** 内容无变化则跳过写入（幂等，行尾归一化防 CRLF 误判），避免时间戳刷新弄脏工作区 ***/
+function writeIfChanged(file, content) {
+  if (fs.existsSync(file) && fs.readFileSync(file, 'utf8').replace(/\r\n/g, '\n') === content) return false;
+  fs.writeFileSync(file, content);
+  return true;
+}
+
 /*** 聚合清单，生成 .ua/index.json 与 llms.txt ***/
 function cmdIndex() {
   const packages = collectManifests();
@@ -66,7 +73,11 @@ function cmdIndex() {
     repoRoot: '.',
     packages,
   };
-  fs.writeFileSync(INDEX_FILE, JSON.stringify(index, null, 2) + '\n');
+  // 幂等：剔除 generatedAt 后内容一致即不写入，连续 check 不弄脏工作区
+  const json = JSON.stringify(index, null, 2) + '\n';
+  const stripTs = (s) => s.replace(/"generatedAt": "[^"]*"/, '"generatedAt": ""');
+  const changed = !fs.existsSync(INDEX_FILE) || stripTs(fs.readFileSync(INDEX_FILE, 'utf8').replace(/\r\n/g, '\n')) !== stripTs(json);
+  if (changed) fs.writeFileSync(INDEX_FILE, json);
 
   const lines = [
     '# @ui-arch 私人组件库索引',
@@ -87,8 +98,8 @@ function cmdIndex() {
     for (const c of p.conventions ?? []) lines.push(`- 约定: ${c}`);
     lines.push('');
   }
-  fs.writeFileSync(LLMS_FILE, lines.join('\n'));
-  console.log(`indexed ${packages.length} package(s) -> .ua/index.json, llms.txt`);
+  writeIfChanged(LLMS_FILE, lines.join('\n'));
+  console.log(`indexed ${packages.length} package(s) -> .ua/index.json, llms.txt${changed ? '' : ' (unchanged, skip)'}`);
 }
 
 /*** 读取注册表索引；缺失则报错退出 ***/