Apply an already-parsed paste payload to the input.
Callers apply a payload through this method rather than posting it as a message so it reaches the document synchronously. Textual appends a posted message to the tail of the receiving widget's FIFO queue, so a keystroke the terminal already delivered would be handled first and land ahead of the paste.
Raw payload text.
Resolved dropped paths, or None to collapse text into a
[Pasted text #N] placeholder.
