Real-Time Device Readout Panel

Part of https://github.com/DiamondLightSource/sm-bluesky/issues/373 Device Readouts:

Build a dedicated telemetry UI component displaying motor positions, setpoints, and live traces. This resolves the current limitation where users have to use external EPICS screens to track positions

### 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

- [ ] Visual Position Tracking: The user can monitor current device positions, setpoints, andl limits in real-time within the main acquisition interface.
- [ ] Continuous Telemetry during Scans: Telemetry coordinates and readbacks must update continuously even during active scan plans when BlueSky is busy.

### Tasks

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

> [!NOTE]
> This is heavily depend on the core infrastructure direction.
> - [ ] EPICS API Client: Integrate an EPICS API connection directly on the UI backend.
> - [ ] PV Polling/Subscription: Set up subscription streams to listen to PVs independent of the BlueSky control loop.
- [ ] UI Readout Panel: Design and layout a telemetry widget for selected devices based on Neeli's proposed design refinements.
- [ ] Traces & Limits Display: Render live positional traces and soft/hard limits for active devices.

## Screen Shoot

Start by reading the parent issue #373 and the repository's existing UI and core infrastructure direction. Identify the entry points for EPICS connectivity, device selection, and the main acquisition interface, then confirm the proposed design refinements. Done means the panel shows positions, setpoints, limits, and live traces, with telemetry continuing during active Bluesky scans.

Written by the indexing model from the issue text.