pub const EVENT_ATTACHMENT_PROGRESS: &str = "attachment:progress";Expand description
Image attachment processing (SPEC_AGENT_PANE_IMAGE_ATTACHMENTS_2026_09_26.md
§6.5). Scoped block:<id> of the pane that started the batch. Payloads are
AttachmentProgressEvent / AttachmentReadyEvent / AttachmentFailedEvent
/ AttachmentBatchDoneEvent in rpc_types::attachments.