Align dashboard UI with upstream observability

[Octane0411]

Problem statement

The TypeScript observability dashboard was functionally live, but the page structure, table design, and UI details were still much more primitive than upstream. Important affordances like state badges, session copy actions, combined runtime/turns, codex update summaries, and token breakdowns were missing.

Scope summary

• rebuild the dashboard HTML structure to align with the upstream observability layout
• restyle the page with upstream-inspired cards, tables, badges, spacing, and responsive behavior
• reshape running session rows into issue/state/session/runtime-codex/tokens presentation
• add the session copy button and improved empty states
• update dashboard tests to lock the new structure in place

References

• Upstream dashboard view: /Users/wangruobing/Personal/symwork/original-symphony/elixir/lib/symphony_elixir_web/live/dashboard_live.ex
• Upstream dashboard stylesheet: /Users/wangruobing/Personal/symwork/original-symphony/elixir/priv/static/dashboard.css
• Upstream presenter: /Users/wangruobing/Personal/symwork/original-symphony/elixir/lib/symphony_elixir_web/presenter.ex

Validation

• pnpm test
• pnpm typecheck
• pnpm lint