Redraw the backdrop and cool the menus down

The court art had three faults: a hard-edged pale panel sitting on the near
half, mown stripes that stopped and restarted where the court began, and the
blood pool stranded behind the baseline where a portrait phone cropped it off.
Redrawn with the stripes running unbroken the full depth and the stain out on
the court where it can be seen.

The picture also read as zoomed in, which was not the art but the crop: at 4:6
`cover` was throwing away a third of the width on a phone. The sky is extended
to 1:2 instead, so the whole arena survives the crop.

Menu palette rotated off olive towards a cool desaturated blue-green with much
quieter borders, and the boxed BEST RUN / WORLD RANK bar is gone from the
splash — it sat on the best part of the art to say what the two buttons under
it already said.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

render.js

@@ -201,7 +201,7 @@ function drawRunOff() {
 // Asset cache-buster — bump with main.js?v=N (see the img.src note below). EXPORTED because the
 // menu screens hang <img> tags on the same files, and two copies of this number is one copy too
 // many: the one that does not get bumped is the one that serves a cached 404.
-export const SPRV = 85;
+export const SPRV = 86;
 const SPR = {};
 for (const n of ['p_idle1','p_idle2','p_bounce','p_bounce2','p_toss','p_smash','p_run1','p_run2','p_run3','p_run4','p_swing1','p_swing2','p_die1','p_die2','p_die3','p_die4','p_die5',
                  'p_pull', // the serve wind-up: the racket dropping behind him while the pull is drawn