docs: document Scheduled Tasks (preview) (cube-js#11126)

Add a docs page for the Scheduled Tasks preview feature, which lets users
save a natural-language agent prompt and run it on a schedule (or on
demand), producing an Analytics Chat thread per run. Covers the task
anatomy, schedule options, management actions, output, conversational
management, and preview limitations. Wire the page into the
Explore & Analyze nav group next to Analytics Chat.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: keydunov

docs-mintlify/docs.json

@@ -93,6 +93,7 @@
                 ]
               },
               "docs/explore-analyze/analytics-chat",
+              "docs/explore-analyze/scheduled-tasks",
               "docs/explore-analyze/skills"
             ]
           },

docs-mintlify/docs/explore-analyze/scheduled-tasks.mdx

@@ -0,0 +1,98 @@
+---
+title: Scheduled Tasks
+description: Save a natural-language agent prompt and have Cube run it automatically on a schedule, producing an Analytics Chat thread for each run.
+---
+
+<Warning>
+
+Scheduled Tasks are currently in preview, and the user experience may still
+change. Reach out to the [Cube support team](/admin/account-billing/support)
+to activate this feature for your account.
+
+</Warning>
+
+Scheduled Tasks let you save a natural-language prompt for the
+[agent](/docs/explore-analyze/analytics-chat) and have Cube run it
+automatically on a schedule — or on demand. Each run produces an
+[Analytics Chat](/docs/explore-analyze/analytics-chat) thread you can open
+later to read the agent's answer.
+
+For example, you might schedule a task to *"every weekday at 9am, summarize
+yesterday's signups and flag anything anomalous"* and review the resulting
+chat each morning.
+
+Scheduled Tasks are **scoped to a deployment** — each task belongs to the
+deployment it was created in.
+
+## Where to find it
+
+In the deployment sidebar, open **Scheduled** (the clock icon, below
+**Explore**). The page lists the deployment's tasks with their name,
+schedule, status, and description, and is searchable.
+
+{/* TODO: screenshot — Scheduled Tasks list page in the deployment sidebar */}
+
+## Anatomy of a task
+
+A task has:
+
+- **Name** (required) — how the task appears in the list.
+- **Description** (optional) — a short summary shown in the list.
+- **Instructions** (required) — the natural-language prompt the agent runs on
+  each execution.
+- **Schedule** — how often the task runs (see below).
+- **Enabled** — a toggle to activate or pause a scheduled task.
+
+## Schedule options
+
+Scheduled Tasks use the same schedule editor as
+[dashboard scheduled refresh](/docs/explore-analyze/scheduled-refreshes),
+offering these frequencies:
+
+- **Manual** — no schedule; the task runs only when you trigger it with
+  **Run now**.
+- **Hourly**, **Daily**, **Weekly** (with a day of the week), and **Monthly**
+  (with a day of the month) — each with a time picker.
+- **Custom** — a raw cron expression for full control.
+
+A **timezone** selector (defaulting to your browser's timezone) controls when
+the schedule fires; it is stored per task.
+
+## Managing tasks
+
+From the list, you can:
+
+- **Create** a new task.
+- **Edit** an existing task's instructions, schedule, or details.
+- **Enable / Pause** a scheduled task to control whether it runs on schedule.
+- **Run now** — trigger a one-off run immediately. This works for both manual
+  and scheduled tasks.
+- **Delete** a task. Deleting removes its schedule and stops all future runs.
+
+## Reading the output
+
+Each run creates an [Analytics Chat](/docs/explore-analyze/analytics-chat)
+thread containing the agent's response. Open the thread from the chat UI to
+read the full answer, ask follow-up questions, or
+[save results to a Workbook](/docs/explore-analyze/workbooks).
+
+The task runs headlessly under the security context of the user who created
+it, so it sees exactly the data that user can access.
+
+## Managing tasks from chat
+
+You can also create and manage Scheduled Tasks conversationally in
+[Analytics Chat](/docs/explore-analyze/analytics-chat). Ask the agent to
+schedule, update, list, or delete tasks in plain language — for example,
+*"schedule a daily summary of yesterday's signups at 9am"* or *"list my
+scheduled tasks."*
+
+## Preview limitations
+
+- Scheduled Tasks must be activated for your account by the
+  [Cube support team](/admin/account-billing/support).
+- Results are delivered only as Analytics Chat threads — there is no email or
+  Slack delivery.
+- Missed runs (for example, while a deployment is unavailable) are not caught
+  up automatically.
+- There is no in-app run-history view yet.