// Copy JSON from Block Kit Builder
contextActionsJSON := `{
    "type": "context_actions",
    "block_id": "feedback",
    "elements": [...]
}`

// Create block (preserves all fields)
block, err := slack.BlockFromJSON(contextActionsJSON)
// or use MustBlockFromJSON() in tests

// Mix with regular blocks
msg := slack.NewBlockMessage(
    slack.NewDividerBlock(),
    block,
    slack.NewSectionBlock(...),
)