SpookiUI v1.13.0 — Pixel-art treat overhaul

Highlights

Lemmings redrawn as chunky pixel-art sprites that now walk up and down a stepped staircase instead of a flat ledge.
Jumper reworked into an NES-style plumber scene: a recognisable red-cap/mustache/overalls sprite, randomly placed ? and brick blocks, the hero jumps only when a block is above him (and the block bumps when hit), plus SMB-style scenery — brick ground, green hills, bushes, drifting clouds, and a shuffling Goomba.
Chomper now reuses the same ghost sprite as the Ghosts treat (factored into a shared ghost_body so the two can't drift apart).
Treat animation is now focus-only: unfocused windows show the plain terminal, or dimmed + desaturated when "dim unfocused" is enabled (requires a Ghostty build that exposes the focus uniform).
Sliders (treat vibrancy and bounded numeric options such as background-opacity) redrawn with width-1 ASCII glyphs so they render correctly at values below 100%.

No config-file or CLI changes. Fully backward compatible — existing configs, profiles, and treats keep working.