v0.7.0

Added

• High-signal dashboard: composite health banner (error rate + queue latency + utilization, with an expandable "why"), top-failing-classes panel (→ filtered Errors + Datadog), and a problem-queues panel.
• Interactive throughput chart: peak readout, hover tooltip, emphasized endpoint.
• Richer metric cards + a new Backlog card.
• Job detail: collapsible large args; full backtrace (was truncated to 20 frames).

Changed

• Extracted failing-job aggregation into RoundhouseUi::ErrorGroups (shared by Errors + dashboard).