Atom++ Agent Sketch: marching-ants running state + activity timeline + Clear confirm

- Running node: green "marching ants" — a dashed stroke that travels around the rounded card
  (SVG stroke-dashoffset), plus a RUNNING badge. Ports sit at z-index 6 so the connector dots
  never flicker (the reason the earlier overlay approach was dropped). Replaces the glow/shimmer.
- Notifications: a professional status pill (kind-colored icon badges) + a read-only "Activity"
  timeline of the last 100 updates (newest first, timestamped) — runs started/finished with the
  token+cost summary, stopped/errored, model switches, board commands, saves, loads, cycle
  rejections. Reworded the model-switch toast ("Switched every agent to X — re-run to update costs").
- Clear now double-confirms via a calm modal (Cancel focused so a stray Enter can't wipe the
  sketch; Esc / backdrop cancel; no-op when already empty). Re-checks `running` AFTER the awaited
  confirm so a run starting while the dialog is open can't wipe the graph mid-run (TOCTOU fix from
  adversarial review).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: ndemianc