Descrizione
Posta un messaggio su un canale Slack via Web API (chat.postMessage). Supporta plain text con emoji, Block Kit (layouts/buttons/sections) e thread reply via thread_ts. Credentials da integration vault → Settings → Integrations → Slack (bot token xoxb-*). Use case: alert workflow runtime, deploy report, daily digest, AI agent reply nel canale. Idempotency-Key auto generata da runId:nodeId per evitare duplicate post su retry. Block Kit reference: api.slack.com/block-kit/building.
