Add a scan progress bar with calculated time-to-completion based on motor speeds and count time etc.

Part of https://github.com/DiamondLightSource/sm-bluesky/issues/373 Queue Management & Experiment Control

Implement visual progress feedback including dynamic progress bars and remaining duration calculations during scan execution

Goals

Acceptance criteria : What journeys should the user be able to complete to consider your feature done
Be as specific as you can, check them off once they work. Add more if you find more requirements during development. Issue should only be considered done after all of them are checked

• The user can view an active scan's execution progress bar with an estimated time remaining.

Tasks

base on the goals, deduce the tasks required. check them off once they're done

• Duration Estimator: Build a calculator using motor speed, acceleration, range, and scan resolution to compute estimated plan runtimes, this most likely will be done with Bluesky simulation or something build into plan direction, to allow estimate of the plan progression.
• Progress Updates API: Subscribe to BlueSky plan event milestones to update progress bar states dynamically.

The issue names no files or tests; start with parent issue #373 and the linked Bluesky simulation documentation, then locate the existing scan execution and UI/API entry points. Trace how motor speed, acceleration, range, resolution, and plan milestones can provide progress and remaining-time data, and verify the active-scan journey meets the stated acceptance criterion.