fix(web-probe): analyze sample timing series

scripts/src/hwlab-node-help.ts

@@ -87,6 +87,7 @@ export function hwlabNodeWebProbeHelp(): Record<string, unknown> {
       "observe start registers a local UniDesk-side observer id under .state/web-observe/index.json; after start, prefer observe status|command|stop|collect|analyze <id> instead of repeating --node/--lane/--state-dir.",
       "observe command actions are explicit user/control actions and are appended to control.jsonl; use --type newSession/selectProvider/sendPrompt/goto/screenshot/mark/stop and keep prompt text out of issue comments by citing textHash/textBytes.",
       "observe analyze is offline-only: it reads artifact JSONL and writes analysis/report.md plus analysis/report.json without accessing Workbench APIs or driving the browser.",
+      "observe analyze scans every sampled DOM point, extracts Workbench timing text such as 总耗时/total and 最近 N 秒/分前, writes sampleMetrics.timeline, and flags backwards/frozen/stale/diagnostic timing anomalies instead of relying on status tail output.",
       "Use recordStep(name, data) or fetchApiMatrix(paths) to keep structured partial evidence when a later step fails.",
       "Use reloadStable(), gotoCurrentStable(), or safeReload() for bounded retries around page reload/current-URL navigation jitter such as ERR_NETWORK_CHANGED.",
       "Playwright page.evaluate accepts one serializable argument; use page.evaluate(({ a, b }) => ..., { a, b }) or safeEvaluate(fn, { a, b }).",