docs(skills): add a timestamp timezone iron rule to the flashduty router

fduty renders timestamps as RFC3339 in the process's local timezone —
Etc/UTC in the AI-SRE runner — so raw strings read as UTC while the user
thinks in their own zone. The card now requires converting to the user's
timezone (per the env block's User Timezone) before quoting any time, and
tagging unconvertible values with their offset.

Author: ysyneu

skills/flashduty/SKILL.md

@@ -33,6 +33,12 @@ Append `--output-format toon` to read commands: it drops the per-row repeated ke
 
 **A result you did not fetch is "unknown", never "empty" — and "fetched" means the same scope, not just the same verb.** You may report a command's result for a given window, entity, or aspect — including "returned empty" or any count/list/finding — **only if a call covering that exact scope appears in your tool-call history this turn**. A wider or different time window, or a sibling entity's result, does not transfer: extrapolating from what you did fetch is the same fabrication as skipping the fetch. If the scope wasn't queried, the honest answer is "未查询 — 可运行 <command>", not a filled-in number or a generalized claim.
 
+## Timestamps — convert before quoting
+
+fduty renders timestamp fields (created_at / updated_at / start_time / …) as **RFC3339 strings in the process's local timezone** in `--json` and `toon` output; unset values stay the bare integer `0`. In the AI-SRE runner the process timezone is **Etc/UTC** (the env block's `Environment Timezone`), so those strings come out **UTC** — not the user's local time. The env block's `User Timezone` (Asia/Shanghai for zh-CN accounts) is the zone the user reads.
+
+**Rule: before quoting ANY fduty timestamp to the user, convert it to the user's timezone** (Asia/Shanghai for zh-CN accounts; the runner env block states `User Timezone`). Report the converted time and label it 北京时间/本地时间. Never present a raw UTC wall-clock as if it were the user's local time — e.g. a change logged at `2026-08-13T13:05:03Z` happened at **21:05 北京时间**, not 13:05. A timestamp you can't convert must be reported with its original offset and an explicit "(UTC)" tag.
+
 ## Command names — don't guess, read the card
 
 The hot path: **read the domain card** (index below) for the exact verb + flags. Command groups are hyphenated (`status-page`, `alert-event`), not concatenated (`statuspage`) — guessing the wrong form costs a failed call. For a command outside the cards, derive it from its API path: **group = first path segment, verb = the rest joined by `-`** (`POST /status-page/change/create` → `fduty status-page change-create`), then confirm with `fduty <group> <verb> --help`. Pass nested-object / array fields as JSON via `--data '{...}'`; typed scalar flags override matching `--data` keys.