Fix terminal detail UX: description wrapping, status contrast, close button ...

- Remove `white-space: nowrap` from `.terminal-detail-meta` and
  `.terminal-item .artifact-meta` — long descriptions now wrap instead
  of being clipped with ellipsis.
- Add `-webkit-line-clamp: 2` to list-item meta so description is
  limited to 2 lines with graceful overflow.
- Fix status colour in detail rows: `.terminal-detail-value.status-busy`
  etc. added after `.terminal-detail-value` so their colours override
  the default #C0CAF5 (was causing light-on-light text).
- Add close button (X) inside `.terminal-detail-header` to dismiss
  the detail pane without leaving the tab.
- Make `selectTerminal` toggle: second click on the same item deselects.
- Build webclient and run tests — all pass.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>