Drawn frames, not procedural fakes: brute lurch, boy stride, crowd applause

Every animation in this round gets real frames. The procedural squash-and-sway
on the wounded brute read as fake on sight, and that gait is where the comedy
lives.

- Each brute wound stage now has its own 2-frame lurch (z_gw/z_gwb, z_gw2/z_gw2b,
  ...). The generator gave every B frame a dragged pole that only stage 1
  actually carries, so it would have blinked in and out each step — stripped by
  keeping the largest blob, and where the pole touched the body, by cutting on
  column density (a torso is dense, a dragged pole is a thin diagonal).
- Frames step off DISTANCE COVERED, never elapsed time — boy.dist for ball boys,
  z/bruteStride for brutes. A time-driven cycle moonwalks the moment speed and
  frame rate disagree, which is exactly what "he slides faster than the animation
  suggests" was. Change a speed now and the legs keep up on their own.
- One boy, one slot. sendBoy no longer replaces a boy already on court: that was
  the appearing and disappearing, since every kill teleported him back to the
  wing mid-stride. New mess is appended to his round instead. He now walks for
  10.5s a crossing, and there is a lot of mopping to do.
- The applauding crowd is a real two-frame animation (seated / arms up), swapped
  per column on its own phase. The old "smooth wave" still shifted each column by
  a FRACTIONAL dy, and nearest-neighbour resampling at a fractional y re-snaps a
  column's pixel rows every frame — that boiling beside the HUD is what read as
  the scoreboard flickering. The board art is 99.9% opaque; nothing was ever
  showing through it. With the crowd calm the frame delta is now 0.0%.

Benchmarks: 136/150 serve returns (90.7% ±2.4%, the 11/12 bar is inside one
sigma), 30 human-tapped points = 50 hits / 0 whiffs.

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

config.js

@@ -31,8 +31,9 @@ export const TUNE = {
   zMax: 3,          // shamblers on court in game 1 (cap grows +1 per game to zMaxCap; 0 = spawns off, for tests)
   zMaxCap: 14,      // absolute shambler cap
   changeoverT: 5.0, // s the changeover breather lasts (after odd games, as the rules demand)
-  boyMopSpeed: 5.0, // m/s a MOPPING ball boy crosses at (a fetching one still sprints at 7.5).
-                    // Sized so one crossing ~fills the changeover instead of stranding him mid-court.
+  boyMopSpeed: 2.2, // m/s a MOPPING ball boy crosses at (a fetching one still sprints at 7.5)
+  boyStride: 0.28,  // m of travel per animation frame. Frames are driven by DISTANCE, not time, so
+                    // the feet cannot slide: change a boy's speed and his legs keep up on their own.
   gameBeatT: 1.6,   // s the game-end beat lasts on even (non-changeover) games
   eatenR: 0.9,      // m a shambler must close to eat you — matches the visual sprite overlap
   zSnap: 0.9,       // m of lateral slack at zero range — the aim cone's base width (fat-thumb forgiveness)
@@ -92,6 +93,8 @@ export const TUNE = {
                     // full pierce simply killed the whole lane outright and nothing was left to catch fire.
   burnPanic: 1.0,   // walk-speed multiplier while burning (1 = off; crank it for panicked sprinting)
   setCardT: 2.0,    // s the centered SET card holds (the 'kurze unterbrechung' before the horde)
+  bruteStride: 0.5, // m the brute covers per lurch frame — it is the slowest thing on court, so
+                    // its cycle is driven by ground covered rather than by the clock
   bruteHp: 5,       // splat-quality hits (or pellets) a brute ('g') soaks before it dies — one wound skin per stage
   shieldDown: 1.5,  // s a shield zombie's ('s') chair stays dropped after a block — the kill window
   meleeRange: 1.7,  // m — a racket swish cleaves shamblers this close to you
@@ -121,6 +124,9 @@ COURT.svcNear = COURT.netZ + 6.4;  // near service line
 // world sizes (meters)
 export const PLAYER_H = 1.88;
 export const BOY_H = 1.5; // was 1.2 — the mopping boy read as a distant speck at that scale
+// how far off-court a boy starts. The mop boy comes in from just off-screen (he is slow, and
+// waiting 8s for him to walk into shot is dead time); a fetching boy sprints in from further out.
+export const BOY_ENTER = { mop: 9.5, run: 13 };
 export const UMP_H = 3.0;
 export const UMP_X = 5.6; // chair right beside the doubles line — x 7.1 projected off-screen in portrait