Create an alert (not metered)

Create an alert that tells the user when a new period of an indicator is published for a place, or when a published value is revised. Use it for "notify me when Spain's CPI is out", "tell me when Texas unemployment is revised", "alert me when my saved chart gets new data". Target: indicator and place (as in get_value), optionally source to follow one publisher only; or workspace_item, the id of a saved chart or table, which follows every place of the item (Pro plan, like the workspace). Channels: "email" (default) to the account's own address, one message per release run or a daily digest with email_mode "daily"; "webhook" to an HTTPS URL, signed with Standard Webhooks headers (Builder and Pro); "feed" for agents that poll list_changes instead. Examples: {"indicator": "cpi_annual_change", "place": "Spain"}. {"indicator": "unemployment_rate", "place": "Texas", "events": ["revision"]}. {"workspace_item": "wsp_3f9a...", "channel": "webhook", "webhook_url": "https://example.com/hooks/invokely"}. Returns {alert: {id, label, target, events, channel, status, ...}, created, secret?, warnings?}. secret (webhooks only) is shown once: tell the user to store it to verify signatures. Free keeps 5 alerts, Builder 50, Pro 500. Alert calls do not use the monthly allowance.