Root cause was NOT WebGL — breadcrumbs showed 141KB single-frame
terminal.write() calls freezing Chrome for 2+ minutes even with the
canvas renderer. During heavy Ink output, multiple SSE terminal events
accumulate between animation frames and flush all at once.
Fix: split flushPendingWrites at DEC 2026 sync segment boundaries with
a 48KB per-frame budget. Each segment is a complete Ink redraw, so
splitting between them preserves atomicity (no flicker). Excess
segments are deferred to the next requestAnimationFrame.
Also re-enable WebGL since it was not the cause — the flush cap
protects both renderers equally.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
