fix: schedule card placement, preview state, and scheduled-workflow docs

docsite/docs/vantage/workflows.md

@@ -147,6 +147,57 @@ A run shows the script that actually executed, not the current library version.
 
 Targets run **in parallel**; steps within one server run **in order**.
 
+## Schedules
+
+A workflow can carry a schedule, and Vantage will start it the same way a person
+would — the same dispatch, the same snapshot, the same run page. A scheduled run
+is an ordinary run with `schedule` recorded as who triggered it.
+
+Open a workflow, choose **Edit**, and tick **Run on a schedule**. The expression
+is standard five-field cron:
+
+```
+minute  hour  day-of-month  month  day-of-week
+```
+
+The presets write cron underneath, so you can start from one and adjust:
+
+| Preset              | Cron        |
+| ------------------- | ----------- |
+| Hourly              | `0 * * * *` |
+| Nightly, 02:00      | `0 2 * * *` |
+| Weekly, Sun 02:00   | `0 2 * * 0` |
+| Monthly, 1st 02:00  | `0 2 1 * *` |
+
+There is no seconds field and no `@daily`-style shorthand. The next three
+occurrences are shown as you type, and they are computed by the server rather
+than the browser, so what you see is exactly what will fire.
+
+### Timezones
+
+A schedule stores an IANA timezone by name — `Europe/London`, not an offset.
+That is what makes a 02:00 job stay at 02:00 across a daylight-saving change
+instead of drifting an hour for half the year. An unknown zone is refused when
+you save it, not at 2am.
+
+### Overlaps are skipped, not queued
+
+If a run of the same workflow is still going when the next occurrence comes
+round, the occurrence is **skipped** and the reason recorded. It is not queued
+behind the running one. A patch workflow that takes longer than its interval
+should fall behind visibly rather than pile up.
+
+### Missed occurrences
+
+If the control plane was not running when an occurrence was due, it still fires
+when the control plane comes back — but only within **one hour** of the due
+time. Anything older is recorded as missed and dropped. A job missed by ten
+minutes during an upgrade should still run; one missed by two days should not
+suddenly fire at lunchtime.
+
+Either kind of skip is shown on the workflow's schedule panel, with the time it
+was due and why it did not run.
+
 ## Watching a run
 
 Step stdout and stderr stream back as chunks, are appended to a log file on the