* server: fix speculation after an image
Pass the actual position to the drafter after an image, instead of the
token count. Affects every drafter, not just DFlash.
* rename draft n_past to pos0
n_past is used to denote number of tokens and this parameter is meant to be a position
* speculative: fix failed to decode mtmd chunk with DFlash
When using DFlash w/ vision models, the drafter memory fails to
allocate new tokens because images report a fixed offset. Stop copying
them to allow the drafter to continue.
* address PR feedback
limit M-RoPE skip to images only, allow audio to pass through. Clean up
comments to align to the updated implementation
Jesus Gulfo