Base64-encoded file bytes, without the data: URL prefix.
Original filename, used for chip display in the omnibar and forwarded to Duck.ai.
MIME type of the file. v1: NTP only sends application/pdf. The field is left as an open string (not an enum) to match Duck.ai's input shape and to let additional types be added later without a schema change.
File attached to a Duck.ai prompt. Shape mirrors Duck.ai's existing
NativePromptFileinput so native forwards entries unchanged. NTP encodes the file in the browser (FileReader.readAsDataURL→ base64) and includes it onomnibar_submitChat.