High idle CPU from infinite CSS animations and cursor blink

[navedr]

Problem

Switchboard consumes ~53% CPU with just 2 idle terminals (at shell prompt, no output). This causes noticeable heat and battery drain on laptops.

Root Causes

1. Cursor blink (fixed in PR #36)

cursorBlink: true in xterm options forces a WebGL repaint cycle every ~500ms per terminal. With multiple idle terminals, this keeps the GPU process and renderer constantly active.

2. Infinite CSS animations

Several sidebar/grid elements use animation: ... infinite which forces Chromium's compositor to run at 60fps even when nothing is visually changing:

• .slug-group-dot.running — pulse-dot 2s ease-in-out infinite
• .grid-card-dot.busy — pulse-dot 1.5s ease-in-out infinite
• .session-item.needs-attention .session-status-dot::before/::after — ripple-out 2s ease-out infinite
• .session-item.cli-busy .session-summary — shimmer-text 3s linear infinite

Each infinite animation costs ~5-10% CPU per visible animated element due to continuous composite passes.

Resolution

Replacing infinite animations with static visual equivalents (solid glow, static ring, static color) while keeping the transient spin-dot animation for cli-busy state:

Element	Before	After
Running session dot	Pulsing opacity	Solid green + glow
Grid card busy dot	Pulsing opacity	Solid green + glow
Needs-attention dot	Expanding ripple rings	Static orange ring
CLI-busy summary text	Shimmer gradient sweep	Static blue color

Results

State	Before	After
2 idle terminals	~53% CPU	~3% CPU
No terminals	~1%	~1%

Tested on macOS M2 Max with Switchboard v0.0.28+.

PR #36 addresses cursor blink. The CSS animation fixes are available in navedr/switchboard@5727325 if you'd like to pull them in.

[abasiri]

Cursor Blink should be in v0.0.29