Display VICE version info in trace

## Description

`ViceBmpClient.vice_info()` is already implemented and returns the VICE version string, but it's never displayed to the user.

## Proposed implementation

- Call `vice_info()` during `populate_initial_state()`
- Set it as an attribute on the Session or C64 object (e.g., `_vice_version`)
- Include it in the C64 `_display` string (e.g., "C64 (VICE 3.8.0)")

## Why this matters

Minor quality-of-life improvement — helps users confirm which VICE version they're debugging against, useful for bug reports and compatibility checks.