Stack:
- Ansi: stdlib-only escape helpers (move, colorize, strip)
- State: rolling view of active rotations + recent events; trims to N
- Renderer: paints header / status / active / recent panels; works against
any IO so tests assert against IO::Memory
- Tui: ties State + Renderer to event bus; coalesces repaints to a tick
interval (default 200ms) to avoid flicker under burst events
Active rotation rows show step progress as a filled-bar (▰▰▰▱). Recent
events list latest 8 with timestamp + severity glyph (✓ / ⚠ / !). The
renderer's pad/center helpers correctly account for ANSI escape widths
when computing visible column width.
9 specs cover ANSI helpers (color codes, cursor move, strip), State
event-to-row mapping with completion bookkeeping and ring-buffer trim,
and Renderer output assertions across empty + active + populated states.