Split native host pinning into standalone pin_memory op
Native page-locked allocations (posix_memalign/mlock) no longer require
libaio or AIO worker threads. Compile the pin manager only in pin_memory
and share it with async_io/gds so bounce-buffer recognition stays process-wide.
Signed-off-by: Olatunji Ruwase <tunji.ruwase@snowflake.com>
Co-authored-by: Cursor <cursoragent@cursor.com>
