UI:
- Full redesign — token-driven CSS with dark-default + light theme, semantic
  color for state (healthy/needs_auth/quota/rate_limited), mono-typed IDs,
  state pill chips with dot markers, colored left-rail per row.
- New stats strip above the banner: Healthy models · Locked · Dispatches 24h
  · Est. saved (vs Claude Sonnet \$3/M anchor). Backend endpoint /api/stats
  reads from the existing dispatch log — no new persistence.
- Unlock banner tightened: 4-col grid (provider · pitch · key-input · signup),
  focus rings and inline verify feedback preserved.
- Missing-your-model form matches the new panel styling.

CLI:
- 'external-agents ui' now auto-opens the browser (same behavior as 'init').
  Pass '--no-open' when running over SSH / tmux where a launched browser is
  wrong. 'init' remains as an alias for backward compat.

Bumps to 0.5.0.

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