Speedup suggestion - hyperion could start rotation snapshots before gridscan results return

There is a brief delay of ~3-4 seconds during which the smargon is idle while we are waiting for gridscan results, potentially we could start the snapshots before we get the first result back, and save some time.

Locate Hyperion's gridscan and rotation-snapshot entry points, then trace the current ordering and wait for gridscan results. Done means rotation snapshots can begin before the first gridscan result returns, the idle delay is reduced, and existing gridscan and snapshot behavior remains correct.

Written by the indexing model from the issue text.