Aesthetics: 3x render res, flatter lens, 4-frame walk cycles, tiered gore

- RES 2 -> 3: phone screens now DOWNSCALE the canvas (crisp pixels) instead
  of upscaling it (soft). Umpire-tap coords un-hardcoded from RES=2.
- Flatter lens: camZ 36 -> 42 with camF scaled per orientation (406/580) so
  the PLAYER stays the same size — far-court zombies render ~25% bigger and
  finally read as individuals from the baseline.
- Smoother animation: 4-frame walk cycles for both classic shamblers and the
  runner's sprint (new sheets, same style anchor; z_a1-4, z_b1-4, z_f1-4).
  Same cycle frequency — frames subdivide the stride. Render falls back to
  2 frames per variant until its sheet loads.
- Tiered gore (GORE_MUL): the more advanced the zombie, the more absurd the
  mess — classics 1x (base bumped 24 -> 30 particles), runner 1.8x, shield
  2.5x, racket boss 3x, brute 4x (120 particles, a scatter of stains, an
  instant size-3 mound).

Verified: fresh origin, canvas 1440px, umpire triple-tap works at RES 3,
all 4 anim frames cycle at the old stride rate, brute kill = 120 parts /
2 stains / size-3 pile, far-court lineup screenshot clearly readable,
portrait layout numbers correct (810x1440, camF 580), tennis 11/12,
no console errors.

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

config.js

@@ -2,7 +2,7 @@
 // the exported consts below are structural values that code shares but the panel doesn't show.
 
 export const TUNE = {
-  camZ: 36, camY: 9, camF: 280, horizon: 40,
+  camZ: 42, camY: 9, camF: 406, horizon: 40, // camF/horizon are per-orientation, set in fitViewport
   gravity: 9.2,            // slightly floaty vs 9.8 for readability
   spinFactor: 0.9,         // extra dive on quality shots (fake topspin)
   bounceY: 0.58, bounceXZ: 0.78,