[vaprdev]

Summary

Slow light (aurora, twinkle, bloom around moving things) nudged hundreds of cells by a level or two of 255 every frame, and each nudge costs terminal output. A post-fit quieten() pass holds back a cell's color change until it reaches 3 levels in some channel; a new glyph always sends its true colors, and colors OpenCode drew are left alone.

 paint()
   fit every cell
   tint
+  quieten()   # keep last frame's color unless it moved ≥ 3 levels

Evidence

Estimated terminal output (engine on the mock screen, teeming, 240 frames), origin/main vs this branch:

	main	after
tundra night	466 KB/s	131 KB/s
ocean day	1078 KB/s	254 KB/s
jungle night	454 KB/s	163 KB/s

Glyph flicker is unchanged. The visible difference is at most 2 levels (diff ×40 on the right):

Verified: typecheck, build, dev/check.ts --quiet --max-ms=60 in octant and quadrant mode, screenshots up to date.

Merge Danger

Door: two-way

Blast Radius: engine output stage; colors may lag by up to 2 levels.