`drop-core` Add transfer speed and ETA to CLI progress output

#### Currently, the CLI shows progress as percentage and bytes transferred, but doesn't display transfer speed or estimated time remaining. This would improve UX significantly for large file transfers.

#### Implementation considerations:
- Calculate speed using a rolling average over the last few seconds to smooth out fluctuations
- Format bytes in human-readable units (KB/s, MB/s, GB/s) based on magnitude
- Calculate ETA based on current transfer speed and remaining bytes

#### Additional improvements:
- Show instantaneous and average speeds
- Add option to toggle between detailed and simple progress display

more info: https://github.com/ARK-Builders/ark-core/pull/101#discussion_r2237244116

Start by locating the CLI progress-output entry point and read the discussion linked from PR #101. Confirm the scope for rolling, instantaneous, and average speed, human-readable units, ETA, and the detailed/simple toggle; done means the agreed output behaves correctly during large transfers.

Written by the indexing model from the issue text.