- TopSessions: show '----------' placeholder when session.firstTimestamp
is empty (Copilot provider yields '' when timestamp is missing)
- DashboardContent: add comment explaining undefined days tri-state
- tests/dashboard.test.ts: cover top-5 selection (fewer than 5 sessions,
tied costs, descending sort) and avg/s returning '-' for zero sessions
Authored-by: AgentSeal <hello@agentseal.org>
