Class SendToAudienceAction

Send a single message template to every record resolved from an AudienceSource (List / View / ad-hoc filter). Wraps the SendToAudience function from @memberjunction/communication-engine so the New Communication UI and any agent/workflow can drive a bulk send through the standard Action API.

Required params:

• Source: JSON-stringified AudienceSource ({kind:'list'|'view'|'adhoc', ...})
• RecipientField: field name on the audience entity holding the recipient address (e.g. 'Email')
• ProviderName: communication provider name (e.g. 'SendGrid')
• ProviderMessageTypeName: provider message type (e.g. 'SingleEmail')
• From: sender address
• Subject, Body: standard message content. Body may include record tokens evaluated by the channel.

Optional params:

• FullNameField: field name for recipient's full name (for "FirstName LastName " formatting)
• BodyTemplate: alternative to Body; the channel renders templating against per-record context
• PreviewOnly: when true, resolve audience + build recipients but do NOT send. Returns counts only.
• Credentials: JSON-stringified per-request credential override

Outputs:

• TotalAudienceSize, WillReceiveCount, SkippedCount, FailedCount
• SkippedRecords: JSON array of {RecordID, Reason, Message}
• PreviewOnly: true|false

Drop-guard contract: this action never deletes any record — it only sends messages. The audience picker in the UI uses Resolve Audience first to preview counts before invoking this.